Properties of Electricity and Related Phenomena：練習問題

What happens to a simple circuit when the switch is moved to the 'OFF' position?

When investigating the magnetic effect of an electric current, which of the following actions will likely increase the strength of a homemade electromagnet?

Electrical appliances are constructed using a combination of conductors and insulators. In an electric kettle, which of the following parts is correctly matched with its material and the primary reason for choosing that material based on its electrical properties?

When constructing a simple electrical circuit to light up a bulb, which component is primarily responsible for supplying the electrical energy required for the bulb to glow?

A student tests several objects in a circuit to see if the bulb lights up. The bulb stays dark when a wooden ruler is used but shines brightly when a metal paperclip is used. What conclusion can be drawn?

To make a small light bulb shine, we must connect it to a battery using wires to form a complete loop. What is this continuous path for electricity called?

Electrical appliances like hair dryers and toasters utilize the thermal effect of current. Briefly explain what happens to the internal wires of these appliances when electricity passes through them.

An electric iron is designed with a metal base and a plastic handle. Based on the properties of materials, explain how this design utilizes both conduction and insulation to function effectively while protecting the user.

An electrical circuit consists of a battery, a switch, several wires, and a light bulb.

(a) For the light bulb to light up, describe the condition the circuit must be in regarding its path.
(b) Why are the copper parts of the wires wrapped in a layer of plastic or rubber? Explain this based on the properties of materials.
(c) If the bulb is working and you touch it, it feels warm. Which phenomenon related to electricity explains this observation?

A student sets up a circuit with two batteries, a switch, and a small light bulb, but the bulb does not light up when the switch is closed.

(a) Suggest three possible reasons why the circuit is failing to work, assuming all components are connected. (3 points)

(b) If the student adds one more battery correctly to the circuit, what will happen to the brightness of the bulb? (2 points)

(c) The student noticed a wire has exposed metal because the plastic coating is torn. Explain why this wire should be replaced immediately, referring to short circuits or safety. (2 points)