2024 Cambridge IGCSE Physics (0625) Practice Paper with Answers

A student wants to find the volume of a single small metal screw. She pours water into a measuring cylinder until the water level is at \(30\text{ cm}^{3}\). She then gently lowers 4 identical metal screws into the water, and the new water level is \(54\text{ cm}^{3}\). What is the volume of one screw?

A beaker containing water is heated from below at one side. A small piece of colored crystal is placed at the bottom to show the movement of the liquid. The colored water is observed to rise directly above the flame. What causes this upward movement?

An electric current of \(0.50\text{ A}\) flows through a filament lamp for a time of \(3.0\text{ minutes}\). What is the total charge that passes through the lamp during this time?

A student wants to determine the density of an irregular metal object of mass
180 g. She pours 100 cm³ of water into a measuring cylinder and then lowers the object into the water. The object is completely submerged and the new reading on the measuring cylinder is 145 cm³. She notices that an air bubble of volume 5 cm³ is trapped underneath the object. What is the actual density of the metal of the object?

A ray of light in a semi-circular glass block is directed towards the centre of the flat face. The angle of incidence at the flat face is \(35^\circ\). The critical angle for this glass-air boundary is \(42^\circ\). What happens to the ray when it reaches the flat face?

A cylindrical metal wire of length \(L\) and cross-sectional area \(A\) has a resistance \(R\). A second wire is made of the same metal. It has a length of \(2L\) and a diameter that is twice the diameter of the first wire. What is the resistance of the second wire?

A student wants to determine the density of steel. She uses 20 identical steel ball bearings. She measures the total mass of the 20 ball bearings on a digital balance as 160 g. Next, she pours 50 cm\(^{3}\) of water into a measuring cylinder, then gently lowers all 20 ball bearings into the water. The new water level in the measuring cylinder is 70 cm\(^{3}\). What is the density of the steel?

An electric motor lifts a crate of mass 45 kg vertically upwards through a height of 8.0 m. This process takes 6.0 s. The acceleration of free fall \(g\) is 10 m/s\(^{2}\). What is the average useful power output of the motor?

Which statement correctly describes a difference between evaporation and boiling of a liquid?

A ray of light strikes a flat, horizontal mirror. The angle between the incident ray and the mirror surface is \(35^\circ\). What is the angle of reflection?

A cyclist travels the first \(100\text{ m}\) of a journey in \(10\text{ s}\), and the remaining \(300\text{ m}\) in \(40\text{ s}\). What is the average speed of the cyclist for the entire journey?

A student places a metal spoon and a plastic spoon into a beaker of hot water. The end of the metal spoon outside the water becomes hot much faster than the end of the plastic spoon. Why does this happen?

A student wants to find the volume of a single small metal sphere. She pours some water into a measuring cylinder and records the initial volume as \( 30\text{ cm}^3 \). She then lowers 50 identical metal spheres into the water so that they are completely submerged. The new volume reading is \( 48\text{ cm}^3 \). What is the average volume of one metal sphere?

Two identical metal containers are filled with equal volumes of hot water. One container has a shiny silver outer surface, and the other has a matt black outer surface. Which container cools down more quickly and why?

An electric current of \( 2.5\text{ A} \) flows through a lamp for a time of \( 4.0\text{ minutes} \). What is the total charge that passes through the lamp during this time?

A student wants to determine the volume of a small irregular stone. She pours some water into a measuring cylinder and reads the volume as \(32\text{ cm}^3\). After gently lowering the stone into the cylinder so that it is completely submerged, the new water level is read as \(57\text{ cm}^3\). What is the volume of the stone?

Which statement about the Sun and the Solar System is correct?

A student places a metal spoon in a cup of hot cocoa. The handle of the spoon becomes hot after a short time. By which process is thermal energy mainly transferred through the metal spoon to the handle?

A student measures the density of an irregularly shaped piece of rock. She first measures its mass as \(70\text{ g}\). Next, she pours water into a measuring cylinder until the volume is \(50\text{ cm}^3\). When the rock is completely submerged in the water, the new volume reading is \(78\text{ cm}^3\). What is the density of the rock?

A metal saucepan with a plastic handle contains water and is placed on a hotplate. Thermal energy is transferred through the metal base of the saucepan and then distributed throughout the water. What are the primary methods of thermal energy transfer through the metal base and through the water?

A steady current of \(0.50\text{ A}\) flows through a resistor in a simple electric circuit. How much electric charge passes through the resistor in a time interval of \(2.0\text{ minutes}\)?

Two identical metal cans, one painted matte black and the other shiny silver, are filled with equal amounts of hot water at \(80\\ ^\circ\text{C}\) and placed in a cool room. Which can cools down more rapidly, and what is the main process of thermal energy transfer involved?

A toy car of mass \(0.50\text{ kg}\) travelling at a velocity of \(4.0\text{ m/s}\) collides with a stationary toy car of mass \(1.50\text{ kg}\). The two cars couple (stick) together during the collision. What is the common velocity of the two cars immediately after the collision?

A \(12.0\text{ V}\) d.c. power supply is connected across a parallel combination of two resistors. One resistor has a resistance of \(4.0\\ \Omega\) and the other has a resistance of \(12.0\\ \Omega\). What is the total current drawn from the power supply?

Two identical metal cans contain equal volumes of hot water at \( 80\ ^\circ\text{C} \). Can X is painted matt black and Can Y is painted shiny silver. Both cans are left in a room at \( 20\ ^\circ\text{C} \). The temperature of the water in Can X decreases more rapidly than the temperature of the water in Can Y.

Which statement explains this observation?

A solid rectangular block has a weight of \( 24\text{ N} \) and dimensions of \( 2.0\text{ cm} \times 3.0\text{ cm} \times 4.0\text{ cm} \).

The block is placed on a flat horizontal table. What is the maximum pressure that the block can exert on the table?

The average distance from the Earth to the Sun is approximately \( 1.5 \times 10^8\text{ km} \). Light travels through space at a speed of \( 3.0 \times 10^8\text{ m/s} \).

How long does it take for light from the Sun to reach the Earth?

A star is much more massive than the Sun. Which sequence correctly shows the stages in the life cycle of this star after it leaves the stable (main sequence) stage?

Two identical metal cans each contain the same mass of hot water at 80 degrees Celsius. Can X is painted matt black and Can Y is painted shiny silver. Both cans are left to cool in a laboratory at a room temperature of 20 degrees Celsius. Which can cools down faster and why?

A student measures the density of an irregularly shaped rock. The mass of the rock is 135 g. She lowers the rock into a measuring cylinder containing 50 cm³ of water. The new water level is 80 cm³. What is the density of the rock?

An object has a mass of 15 kg on the Earth, where the gravitational field strength \(g\) is 10 N/kg. The object is taken to the Moon, where the gravitational field strength \(g\) is 1.6 N/kg. What are the mass and the weight of the object on the Moon?

A sound wave is produced by a signal generator connected to a loudspeaker. The frequency of the sound wave is increased, and its amplitude is decreased. How do the pitch and the loudness of the sound change?

A solid rectangular block of mass 4.0 kg has dimensions \(0.10\text{ m} \times 0.20\text{ m} \times 0.40\text{ m}\). The block is placed on a flat horizontal table. The gravitational field strength \(g\) is 10 N/kg. What is the minimum pressure that the block can exert on the table?

A measuring cylinder contains \(40\text{ cm}^3\) of water. A metal object of mass \(120\text{ g}\) is lowered into the cylinder, and the water level rises to \(80\text{ cm}^3\). A second, identical metal object is lowered into the same cylinder. What is the final reading on the measuring cylinder, and what is the density of the metal?

Two identical metal cans are filled with equal volumes of hot water at the same initial temperature. Can X is painted matt black and Can Y is painted shiny silver. Both cans are left in a cool room. Which statement correctly describes and explains which can cools down faster?

A bar magnet is pushed into a solenoid connected to a sensitive center-zero galvanometer. The pointer of the galvanometer deflects momentarily to the right. Which action will cause a larger momentary deflection of the pointer to the left?

A student determines the density of an irregularly shaped stone. The student measures the mass of the stone as \( 150\text{ g} \). The student then lowers the stone into a measuring cylinder containing \( 60\text{ cm}^3 \) of water. The water level rises to \( 85\text{ cm}^3 \). What is the density of the stone?

A student heats one end of a copper rod. Thermal energy is transferred to the cooler end of the rod. Which process is mainly responsible for this transfer of thermal energy, and how does it occur?

An electric current of \( 1.5\text{ A} \) passes through a heating element for \( 4.0\text{ minutes} \). What is the total charge that passes through the heating element in this time?

A uniform metre rule is pivoted at its centre (the \(50\text{ cm}\) mark). A weight of \(3.0\text{ N}\) is hung from the rule at the \(20\text{ cm}\) mark.

At which mark on the rule must a \(2.0\text{ N}\) weight be hung to balance the rule?

An object of mass \(180\text{ g}\) is made of a metal of density \(9.0\text{ g/cm}^3\). The object has an internal, completely sealed hollow cavity. When the object is fully submerged in a measuring cylinder containing water, the water level reading increases from \(40\text{ cm}^3\) to \(75\text{ cm}^3\).

What is the volume of the hollow cavity?

Light from a distant galaxy is redshifted.

Which row correctly describes the motion of the galaxy relative to Earth, the frequency of the observed light compared to the frequency emitted, and what this indicates about the Universe?

- Option A: Motion of galaxy: moving away from Earth; Frequency of light: lower; Indication: the Universe is expanding
- Option B: Motion of galaxy: moving away from Earth; Frequency of light: higher; Indication: the Universe is contracting
- Option C: Motion of galaxy: moving towards Earth; Frequency of light: lower; Indication: the Universe is expanding
- Option D: Motion of galaxy: moving towards Earth; Frequency of light: higher; Indication: the Universe is contracting

Two cylindrical resistors, X and Y, are made of the same uniform metal. Resistor X has length \(l\) and radius \(r\). Resistor Y has length \(2l\) and radius \(2r\).

The resistors are connected in parallel across a power supply of constant potential difference \(V\).

What is the ratio of the current in X to the current in Y, \(\frac{I_{\text{X}}}{I_{\text{Y}}}\)?

A block of mass 2.0 kg is pulled up a rough slope by a constant force of 25 N parallel to the slope. The length of the slope is 5.0 m and its vertical height is 3.0 m. The block starts from rest at the bottom of the slope and reaches a speed of 5.0 m/s at the top. Take the acceleration of free fall, g, as 9.8 m/s^2. What is the work done against friction as the block moves up the slope?

A uniform beam of weight 30 N and length 4.0 m is pivoted at a point 1.0 m from its left end. A load of 50 N is hung from the left end of the beam. Where must a downward vertical force of 10 N be applied to keep the beam in horizontal equilibrium?

Wire X and Wire Y are made of the same metal. Wire X has length \(L\) and cross-sectional radius \(r\). Wire Y has length \(3L\) and cross-sectional radius \(2r\). The resistance of Wire X is \(8.0\ \Omega\). What is the resistance of Wire Y?

A ray of light in a glass block of refractive index 1.50 is incident on the boundary with air at an angle of incidence of 45 degrees. What is the critical angle for the glass-air boundary, and what happens to this ray of light?

A uniform metal wire of resistance R is stretched so that its length doubles, while its volume remains constant. What is the new resistance of the stretched wire in terms of R?

An electric motor is used to lift a load of 120 N through a vertical height of 5.0 m in a time of 4.0 s. The electrical power input to the motor is 200 W. What is the efficiency of the motor?

An electric motor is used to lift a crate of mass \(50\text{ kg}\) vertically through a height of \(6.0\text{ m}\) in a time of \(5.0\text{ s}\). The electrical power supplied to the motor is \(800\text{ W}\). What is the efficiency of the motor? (Use \(g = 9.8\text{ m/s}^2\))

A wire of length \(L\) and circular cross-sectional area \(A\) has a resistance \(R\). A second wire made of the exact same material has a length of \(3L\) and a diameter that is twice the diameter of the first wire. What is the resistance of the second wire?

A ray of light in glass is incident on a boundary with air. The refractive index of the glass is \(1.50\). The angle of incidence is \(40^\circ\). What happens to the ray at the boundary?

A ray of monochromatic light travels inside a semicircular glass block of refractive index (n = 1.60). It is incident on the flat boundary with air at an angle of incidence (\theta). What is the minimum angle of incidence (\theta) for which the light is totally internally reflected, and what happens if (\theta) is reduced to (30.0^\circ)?

A toy car of mass (0.50\text{ kg}) travels in a straight line on a frictionless horizontal surface. It is initially moving at a speed of (2.0\text{ m/s}). A constant braking force of (3.0\text{ N}) is applied to the car in the direction opposite to its motion for a duration of (0.50\text{ s}). What is the final speed and direction of motion of the toy car?

A metal wire of length (L) and circular cross-section of radius (r) has a resistance (R). A second wire is made of the same metal but has a length of (3L) and a cross-sectional radius of (2r). What is the resistance of the second wire in terms of (R)?

Liquid X has a density of \(0.80\text{ g/cm}^3\) and a volume of \(100\text{ cm}^3\). Liquid Y has a density of \(1.20\text{ g/cm}^3\) and a volume of \(300\text{ cm}^3\). The two liquids are mixed together thoroughly. Assuming no change in total volume occurs, what is the density of the mixture?

A step-up transformer has 200 turns on its primary coil and 1000 turns on its secondary coil. The primary coil is connected to a \(12\text{ V}\) d.c. power supply. What is the output voltage across the secondary coil?

Which row correctly shows the sequence of stages in the life cycle of a star with a mass much larger than the Sun?

A tall cylindrical container contains a layer of liquid X of depth \(0.15\text{ m}\) floating on top of a layer of liquid Y of depth \(0.25\text{ m}\). Liquid X has a density of \(800\text{ kg/m}^3\) and liquid Y has a density of \(1200\text{ kg/m}^3\). The atmospheric pressure acting on the surface of liquid X is \(1.0 \times 10^5\text{ Pa}\). The acceleration of free fall \(g\) is \(9.8\text{ m/s}^2\). What is the total pressure at the bottom of the container?

A potential divider circuit consists of a fixed resistor of resistance \(6.0\text{ k}\Omega\) in series with a light-dependent resistor (LDR) connected across a \(12\text{ V}\) d.c. power supply of negligible internal resistance. A voltmeter is connected across the LDR. In bright light, the resistance of the LDR is \(2.0\text{ k}\Omega\). In darkness, the resistance of the LDR is \(18\text{ k}\Omega\). What is the change in the reading on the voltmeter when the light level changes from bright light to darkness?

A distant galaxy is observed to have a recession velocity of \(1.54 \times 10^6\text{ m/s}\). Using the Hubble constant value of \(H_0 = 2.2 \times 10^{-18}\text{ s}^{-1}\), what is the estimated distance from Earth to this galaxy?

A distant galaxy is observed from Earth. The galaxy is at a distance of \(1.5 \times 10^{24}\text{ m}\) from Earth. The Hubble constant \(H_0\) is \(2.2 \times 10^{-18}\text{ s}^{-1}\). What is the speed at which this galaxy is moving away from Earth?

An ideal step-down transformer has a primary coil with \(1200\) turns and a secondary coil with \(300\) turns. The primary coil is connected to a \(240\text{ V}\) a.c. mains supply. A \(6.0\ \Omega\) resistor is connected across the secondary coil. What is the current in the primary coil?

Liquid P has a density of \(0.80\text{ g/cm}^3\) and a volume of \(150\text{ cm}^3\). Liquid Q has a density of \(1.20\text{ g/cm}^3\) and a volume of \(250\text{ cm}^3\). The two liquids are mixed together thoroughly. Assuming there is no change in total volume when they are mixed, what is the density of the mixture?

A metal wire of length \(L\) and cross-sectional area \(A\) has a resistance \(R\). A second wire is made of the same metal. It has length \(3L\) and a circular cross-section with twice the radius of the first wire. What is the resistance of the second wire?

A distant galaxy is located at a distance of \(2.0 \times 10^{22}\text{ m}\) from Earth. The Hubble constant is estimated to be \(2.2 \times 10^{-18}\text{ s}^{-1}\). What is the speed of recession of this galaxy?

A trolley of mass \(2.0\text{ kg}\) travelling at \(6.0\text{ m/s}\) collides with a stationary trolley of mass \(4.0\text{ kg}\). The two trolleys couple together during the collision. What is their common speed after the collision?

A ray of monochromatic light travels inside a glass block of refractive index \( 1.60 \). The ray strikes the flat boundary between the glass and air at an angle of incidence of \( 40.0^\circ \).

What is the behavior of the light ray at the boundary?

A toy car of mass \( 0.50 \text{ kg} \) is moving to the right at a speed of \( 4.0 \text{ m/s} \). It collides with a wall and rebounds to the left at a speed of \( 2.0 \text{ m/s} \). The collision lasts for \( 0.15 \text{ s} \).

What is the magnitude of the average force exerted by the wall on the car?

A cylindrical metal wire of length \( L \) and diameter \( d \) has a resistance \( R \).

A second wire is made of the same metal. It has a length of \( 2L \) and a diameter of \( 2d \).

What is the resistance of the second wire in terms of \( R \)?

An ideal step-down transformer is connected to a \(240\text{ V}\) a.c. supply. The primary coil has \(1000\) turns. The transformer has two separate secondary coils: Coil A has \(100\) turns and is connected to a \(12\ \Omega\) resistor. Coil B has \(50\) turns and is connected to a \(3.0\ \Omega\) resistor. What is the current in the primary coil?

A ray of light traveling inside a glass block of refractive index \(1.50\) is incident on the flat boundary with an unknown liquid. The critical angle for total internal reflection at this boundary is \(60^\circ\). What is the refractive index of the liquid?

A specific spectral line in the light from a distant galaxy has an observed wavelength of \(612\text{ nm}\). In a laboratory on Earth, this same line has a wavelength of \(600\text{ nm}\). The Hubble constant \(H_0\) is \(2.0 \times 10^{-18}\text{ s}^{-1}\) and the speed of light \(c\) is \(3.0 \times 10^8\text{ m/s}\). What is the approximate distance from Earth to this galaxy?

A trolley X of mass 2.0 kg is moving at a speed of 6.0 m/s. It collides with a stationary trolley Y of mass 4.0 kg. The two trolleys stick together and move off with a common velocity. What is the total kinetic energy of the two trolleys after the collision?

An electric heater of power 50 W is used to heat 0.20 kg of a liquid in a well-insulated container. The temperature of the liquid increases by 15 °C in 2.0 minutes. What is the specific heat capacity of the liquid?

A metal wire of length L and cross-sectional area A has a resistance of R. A second wire, made of the same metal, has a length of 2L and a diameter that is twice the diameter of the first wire. What is the resistance of the second wire?

Wire X has length \(l\) and diameter \(d\). Wire Y, made of the same material, has length \(3l\) and diameter \(2d\). The resistance of wire X is \(12\ \Omega\). What is the resistance of wire Y?

An object is placed at a distance of 15 cm from a thin converging lens of focal length 10 cm. Which row describes the nature, orientation, and size of the image formed?

Two identical metal cans, one painted matt black and the other painted shiny silver, are filled with the same mass of hot water at 90 °C. They are left to cool in a room at 20 °C. The water in the matt black can cools more rapidly. Which statement explains this result?

A uniform metal wire of length \(L\) and radius \(r\) has a resistance \(R\). A second wire is made of the same metal but has length \(2L\) and radius \(3r\). What is the resistance of the second wire?

Placeholder

A uniform metal wire of length \(L\) and radius \(r\) has a resistance \(R\). A second wire is made of the same metal but has length \(2L\) and radius \(3r\). What is the resistance of the second wire?

A ray of light in air strikes the flat surface of a glass block.

(a) State the name of the imaginary line drawn at \(90^\circ\) to the glass surface at the point where the light ray enters.

(b) The angle of incidence of the light ray is \(45^\circ\). The light ray bends towards the normal as it enters the glass. State whether the angle of refraction is greater than, equal to, or less than \(45^\circ\).

(c) The speed of light in air is \(3.0 \times 10^8\text{ m/s}\) and its speed in the glass is \(2.0 \times 10^8\text{ m/s}\). Calculate the refractive index of the glass. Show your working.

(d) Explain why the light ray does not bend when it leaves the glass block through a curved boundary along the normal.

A toy car is released from rest and moves down a ramp. Its motion is recorded.

(a) Describe how the speed of the toy car changes if its acceleration is constant and positive.

(b) A speed-time graph for the car shows:
- Speed increases from \(0\text{ m/s}\) to \(4.0\text{ m/s}\) in \(5.0\text{ s}\).
- Speed remains constant at \(4.0\text{ m/s}\) for another \(10.0\text{ s}\).

(i) Calculate the acceleration of the toy car during the first \(5.0\text{ s}\). Include the unit.

(ii) Calculate the total distance traveled by the car during the entire \(15.0\text{ s}\).

A student sets up a circuit to measure the resistance of a wire.

(a) State the name of the instrument used to measure:
(i) electrical current
(ii) potential difference (voltage)

(b) The current in the wire is \(0.40\text{ A}\). Calculate the charge that passes through a point in the wire in \(2.0\text{ minutes}\). Show your working.

(c) The potential difference across the wire is \(6.0\text{ V}\). Calculate the resistance of the wire. State the unit of resistance.

An experiment is carried out to find the density of an irregularly shaped piece of mineral.

(a) State the name of the measuring instrument used to find the mass of the mineral.

(b) The mass of the mineral is found to be \(108\text{ g}\). The mineral is then placed into a measuring cylinder containing water. The initial volume of water is \(55\text{ cm}^3\). When the mineral is fully submerged, the water level rises to \(95\text{ cm}^3\).
(i) Calculate the volume of the mineral.
(ii) Calculate the density of the mineral. State the formula used and show your working.

(c) Describe how the student could adapt this experiment to determine the density of a block of wood that floats in water.

A student stands \(150\text{ m}\) away from a tall brick wall. She claps two wooden blocks together and hears an echo.

(a) Explain what is meant by an echo.

(b) She claps the blocks regularly so that each clap coincides with the echo of the previous clap. The total time for 20 complete round trips of sound is \(18.0\text{ s}\).
(i) Calculate the time interval between one clap and its echo.
(ii) Calculate the speed of sound in air from these measurements. Show your working.

(c) State how the sound heard by the student changes if the frequency of the sound is increased.

A student sets up a circuit consisting of a \(6.0\text{ V}\) battery connected in series with a switch, an ammeter, and a resistor.

(a) State the quantity measured by the ammeter.

(b) When the switch is closed, the reading on the ammeter is \(0.25\text{ A}\).
(i) Calculate the charge that passes through the resistor in \(2.0\text{ minutes}\). State the unit.
(ii) Calculate the resistance of the resistor.

(c) The temperature of the resistor increases. State what happens to the resistance of a typical metal wire resistor as its temperature rises.

A student wants to determine the density of an irregularly shaped stone.
(a) Describe how the student can find the volume of the stone using a measuring cylinder containing some water. [3]
(b) The mass of the stone is measured using a balance and is found to be \( 54.0\text{ g} \). When the stone is lowered into the measuring cylinder, the water level rises from \( 30.0\text{ cm}^3 \) to \( 50.0\text{ cm}^3 \). Calculate the density of the stone. [3]
(c) State the safety precaution the student should take when lowering the stone into the glass measuring cylinder. [1]

A solar panel is used to heat water for a house. The water flows through copper pipes painted matte black behind a glass cover.
(a) Explain why the copper pipes are painted matte black. [2]
(b) Explain why copper is a suitable material for the pipes. [2]
(c) Explain how the glass cover helps to reduce thermal energy loss by convection. [3]

A circuit contains a \( 9.0\text{ V} \) battery connected in series with two resistors of resistance \( 6.0\\ \Omega \) and \( 12.0\\ \Omega \).
(a) Calculate the total combined resistance of the two resistors in series. [2]
(b) Calculate the current in the circuit. [2]
(c) Describe how the total resistance of the circuit changes if the \( 12.0\\ \Omega \) resistor is replaced by one with a lower resistance. [1]
(d) State the function of a fuse in such a circuit. [2]

A student heats water in a metal saucepan on a hotplate.

(a) State the main process by which thermal energy is transferred through:
(i) the metal bottom of the saucepan,
(ii) the water inside the saucepan.

(b) Describe, in terms of particles (atoms/electrons), how thermal energy is transferred through the metal bottom of the saucepan.

(c) The outside of the saucepan is highly polished and shiny. Explain how this helps to keep the food inside hot for a longer time after the saucepan is removed from the heat source.

A ray of light is incident on the flat face of a rectangular glass block.

(a) Define the term *refraction*.

(b) The angle of incidence in air is \(45^\circ\) and the angle of refraction in the glass is \(28^\circ\).
(i) Calculate the refractive index of the glass. Show your working.
(ii) State what happens to the speed of light as it enters the glass block.

(c) Under certain conditions, total internal reflection occurs at the boundary. State the two conditions required for total internal reflection to happen.

A small toy car A of mass 0.40 kg is moving at a velocity of 3.0 m/s along a frictionless horizontal track. It collides with a stationary toy car B of mass 0.60 kg. After the collision, car A rebounds in the opposite direction at a speed of 0.60 m/s. (a) Calculate the momentum of car A before the collision. (b) Calculate the velocity of car B after the collision. (c) The collision lasts for 0.15 s. Calculate the average force exerted on car A during the collision and state its direction.

A metal block is heated to a high temperature. One half of its outer surface is painted matte black, and the other half is painted shiny silver. The block is suspended inside a vacuum chamber. (a) State and explain the method of thermal energy transfer from the block to the surroundings, explaining why other methods cannot occur in a vacuum. (b) Two identical temperature sensors are placed equal distances from the block: Sensor X faces the black side and Sensor Y faces the silver side. State and explain which sensor will detect a faster rate of temperature rise. (c) In a separate setup, the same hot block is suspended in air. Describe how convection currents are set up in the air surrounding the block.

A student conducts an experiment with a solenoidal coil connected to a sensitive center-zero galvanometer. The student pushes the North pole of a bar magnet into the left-hand end of the coil. (a) Explain why a deflection is observed on the galvanometer as the magnet enters the coil. (b) State Lenz's law and use it to identify the magnetic pole induced at the left-hand end of the coil as the North pole enters. (c) The student now pulls the magnet out of the coil at a much higher speed than it was inserted. Compare the deflection on the galvanometer during removal with the deflection during insertion, explaining the differences.

A student investigates electromagnetic induction using a coil of wire connected to a sensitive center-zero galvanometer and a bar magnet.

(a) Explain what is meant by electromagnetic induction. [2]

(b) The student pushes the north pole of the bar magnet into the coil.
(i) Describe and explain the deflection observed on the galvanometer during this action. [3]
(ii) State two changes to the procedure that would increase the magnitude of the deflection on the galvanometer. [2]
(iii) The magnet is then held completely stationary inside the coil. State the reading on the galvanometer. [1]

Our understanding of the Universe is built on observations of stars and distant galaxies.

(a) State what is meant by redshift and explain how it supports the Big Bang theory of the origin of the Universe. [3]

(b) Explain the difference between a stable main sequence star and a supernova, in terms of the balance of forces acting within them. [2]

(c) A distant galaxy is observed to be moving away from the Earth at a speed of \(4.4 \times 10^6\text{ m/s}\).
(i) Calculate the distance of this galaxy from Earth in meters. Use the Hubble constant \(H_0 = 2.2 \times 10^{-18}\text{ s}^{-1}\). [2]
(ii) Convert this distance into light-years. Use the speed of light \(c = 3.0 \times 10^8\text{ m/s}\) and \(1\text{ year} = 3.15 \times 10^7\text{ s}\). [1]

An experiment is set up to determine the specific heat capacity of aluminum. An aluminum block of mass \(0.80\text{ kg}\) is heated using a \(40\text{ W}\) electrical heater for \(5.0\text{ minutes}\). The temperature of the block rises from \(20^\circ\text{C}\) to \(35^\circ\text{C}\).

(a) Define specific heat capacity. [2]

(b)(i) Calculate the electrical energy supplied to the heater during the \(5.0\text{ minutes}\). [2]
(ii) Calculate the experimental value for the specific heat capacity of aluminum. [2]
(iii) Explain why the experimental value calculated in (b)(ii) is likely to be greater than the actual accepted value for aluminum. Suggest one practical modification to the setup to reduce this error. [2]

An alternating current (a.c.) generator consists of a rectangular coil rotating in a uniform magnetic field.

(a) Explain why an electromotive force (e.m.f.) is induced in the coil as it rotates. [3]

(b) State two ways to increase the maximum value of the induced e.m.f. [2]

(c) The output of the generator is connected to a step-up transformer. The primary coil of the transformer has 200 turns and is connected to an input voltage of \(12\text{ V}\) a.c. The secondary coil has 1500 turns.

(i) Calculate the output voltage of the transformer. [2]

(ii) Assuming the transformer is \(100\%\) efficient and the current in the secondary coil is \(0.080\text{ A}\), calculate the current in the primary coil. [1]

(a) Describe the life cycle of a star that is much more massive than our Sun, starting from its stable main sequence stage until its final stage. [4]

(b) Light emitted from a distant galaxy is observed to be redshifted.

(i) Explain what is meant by the term redshift. [2]

(ii) State and explain how redshift provides evidence for the Big Bang theory. [2]

A rectangular block of concrete has dimensions \(0.50\text{ m} \times 0.40\text{ m} \times 1.2\text{ m}\). The density of concrete is \(2400\text{ kg/m}^3\).

(a) The block is placed on flat, horizontal ground.

(i) Calculate the mass of the block. [2]

(ii) Calculate the minimum pressure that the block can exert on the ground. (Take the acceleration of free fall \(g = 9.8\text{ m/s}^2\)) [3]

(b) A U-tube manometer containing water of density \(1000\text{ kg/m}^3\) is connected to a gas supply. The difference in the water levels between the two columns is \(25\text{ cm}\).

Calculate the difference in pressure between the gas supply and the atmosphere. [3]

(a) Define specific heat capacity. [2]

(b) An electric heater of power 45 W is used to heat a metal block of mass 1.2 kg. The heater is switched on for 6.0 minutes. The temperature of the block rises from 20 °C to 45 °C.

(i) Calculate the specific heat capacity of the metal, assuming no thermal energy is transferred to the surroundings.

Specific heat capacity = ................................... J/(kg °C) [3]

(ii) In practice, some thermal energy is lost to the surroundings during the heating process. State and explain the effect of this thermal energy loss on the calculated value of the specific heat capacity. [3]

A student investigates the rate of cooling of water in a beaker under different conditions. They set up a beaker containing hot water with no lid, and record its temperature every 60 seconds for 3 minutes. They then repeat the procedure using a beaker with a cardboard lid. (a) Figure 1.1 shows a diagram of the thermometer at the start of the first experiment (no lid). The meniscus of the thermometer liquid is aligned with the mark exactly halfway between 84 and 85 °C. Record this initial temperature \(\theta_0\). (b) The student's recorded temperatures are shown: With no lid: \(t = 0\text{ s}\), \(\theta = \theta_0\); \(t = 60\text{ s}\), \(\theta = 76.5^\circ\text{C}\); \(t = 120\text{ s}\), \(\theta = 70.0^\circ\text{C}\); \(t = 180\text{ s}\), \(\theta = 65.0^\circ\text{C}\). With cardboard lid: \(t = 0\text{ s}\), \(\theta = \theta_0\); \(t = 60\text{ s}\), \(\theta = 79.5^\circ\text{C}\); \(t = 120\text{ s}\), \(\theta = 75.0^\circ\text{C}\); \(t = 180\text{ s}\), \(\theta = 71.5^\circ\text{C}\). (i) Calculate the temperature drop \(\Delta\theta_1\) during the first 180 s for the beaker with no lid, including the correct unit. (ii) Calculate the temperature drop \(\Delta\theta_2\) during the first 180 s for the beaker with the cardboard lid, including the correct unit. (c) Suggest two precautions that should be taken in this experiment to ensure the temperature readings are accurate. (d) State whether the cardboard lid significantly reduces the cooling rate. Justify your answer by reference to the results. (e) The student wants to extend the experiment to investigate how the material of the lid affects the rate of cooling. Identify two variables that must be kept constant.

A student investigates the focal length \(f\) of a converging lens by obtaining a sharp image of an illuminated object on a screen. (a) Figure 2.1 shows a diagram of the experimental setup, drawn to a scale of 1:5. On the diagram, the distance representing the object-to-lens distance is measured as \(x = 4.0\text{ cm}\), and the distance representing the lens-to-screen distance is measured as \(y = 8.0\text{ cm}\). (i) State the actual distance \(u\) from the object to the lens, in cm, using the scale. (ii) State the actual distance \(v\) from the lens to the screen, in cm, using the scale. (b) Calculate the focal length \(f_0\) of the lens using the equation: \(f = \frac{uv}{u+v}\). (c) The student repeats the procedure for several positions, yielding the values in Table 2.1. Table 2.1: Run 1: \(u = 25.0\text{ cm}\), \(v = 50.0\text{ cm}\); Run 2: \(u = 30.0\text{ cm}\), \(v = 37.5\text{ cm}\); Run 3: \(u = 40.0\text{ cm}\), \(v = 26.7\text{ cm}\). (i) For Run 1, Run 2, and Run 3, calculate the values of the focal length \(f_1\), \(f_2\), and \(f_3\). (ii) Calculate the average focal length \(f_{\text{avg}}\) of the lens from these three runs. (d) State one difficulty in obtaining an accurate, sharp image on the screen in this experiment, and suggest how the student can overcome it. (e) Why is it important to perform this experiment in a darkened room?

A student investigates the resistance of a constantan wire. They set up a circuit to measure the current in the wire and the potential difference across various lengths \(L\) of the wire. (a) Draw a circuit diagram containing a cell, a switch, an ammeter, a voltmeter, and a length of resistance wire \(XY\) connected in series, with the voltmeter connected in parallel across the wire \(XY\. (b) The student connects the voltmeter across a length \)L = 40.0\text{ cm}\) of the wire. The ammeter shows a reading of 0.32 A, and the voltmeter shows a reading of 1.28 V. Record the current \(I\) and potential difference \(V\). (c) Calculate the resistance \(R\) of this \(40.0\text{ cm}\) length of wire. (d) The student records the resistance for other lengths as shown: \(L = 20.0\text{ cm}\): \(R = 1.98\ \Omega\); \(L = 60.0\text{ cm}\): \(R = 6.02\ \Omega\); \(L = 80.0\text{ cm}\): \(R = 8.01\ \Omega\). (i) Calculate the ratio \(\frac{R}{L}\) for each length (including the \(40.0\text{ cm}\) length). State the unit for this ratio. (ii) State whether your values for \(\frac{R}{L}\) suggest that the resistance \(R\) is directly proportional to the length \(L\) of the wire. Justify your answer by reference to your calculated ratios. (e) Explain why the switch should be opened between readings.

A student is determining the focal length \(f\) of a convex lens in a practical experiment. (a)(i) The student sets up the apparatus on an optical bench. The illuminated object is placed at the 0.0 cm mark. The lens is placed at the 20.0 cm mark, so the object distance \(u = 20.0\text{ cm}\). The screen is moved until a sharp image of the object is formed on it. The screen is at the 60.2 cm mark. Calculate the image distance \(v\) from the lens. (ii) Calculate the focal length \(f_1\) using the formula: \(f_1 = \frac{u \times v}{u + v}\). (b)(i) The lens is then moved to the 30.0 cm mark, so \(u = 30.0\text{ cm}\). A sharp image is formed when the screen is at the 60.1 cm mark, giving \(v = 30.1\text{ cm}\). Calculate the focal length \(f_2\) using the same formula. (ii) Calculate the average focal length \(f_{\text{avg}}\) of the lens. (c) State two practical precautions that should be taken in this experiment to obtain accurate position readings. (d) Describe the shape of the graph of \(v\) against \(u\) and explain how the value of \(f\) can be determined from the point on the graph where \(u = v\). (e) State one characteristic of the image other than it being inverted when \(u = 30.0\text{ cm}\). (f) State why it is difficult to determine the exact position of the screen for the sharpest image.

A student investigates how the resistance of a constantan wire depends on its length. The student sets up a circuit with a power source, an ammeter, a voltmeter connected across a variable length L of the wire, and a sliding contact. (a) (i) For a length of wire L = 20.0 cm, the student records a potential difference V = 1.20 V and a current I = 0.80 A. Calculate the resistance R of this length of wire, and state its unit. (ii) State one practical precaution the student should take when measuring the length L of the wire to ensure that the measurement is accurate. (b) The incomplete table shows the student's measurements and calculated resistance values. Table: Length L / cm | Potential Difference V / V | Current I / A | Resistance R / \(\Omega\). Row 1: 20.0 | 1.20 | 0.80 | [to be calculated]. Row 2: 40.0 | 1.80 | 0.60 | 3.00. Row 3: 60.0 | 2.16 | 0.48 | 4.50. Row 4: 80.0 | 2.40 | 0.40 | 6.00. Row 5: 100.0 | 2.55 | 0.34 | 7.50. (i) Complete the table by writing in the value of the resistance for L = 20.0 cm. (ii) State why it is important to record the values of resistance to the same number of significant figures or decimal places as the other calculated resistance values in the table. (c) Another student suggests that the resistance R of the wire is directly proportional to its length L. (i) State how the data can be used to test this suggestion by calculating a constant ratio. (ii) Calculate the value of the ratio R/L for L = 40.0 cm and for L = 80.0 cm. Include the unit for this ratio. (iii) State whether your results from (c)(ii) support the suggestion. Justify your answer by referring to your calculations. (d) Current passing through the wire causes it to warm up during the experiment. (i) State the effect that a temperature rise has on the resistance of a metal wire. (ii) Suggest one practical method used in this experiment to minimize the heating effect of the current.