Use of SI units and their prefixes：練習問題

Which of the following is equivalent to \( 1 \text{ GV} \)?

A laser produces light with a wavelength of \(633 \text{ nm}\). What is this wavelength in micrometres (\(\mu\text{m}\))?

The activity of a radioactive sample is measured in Becquerels (Bq), where \( 1 \text{ Bq} = 1 \text{ s}^{-1} \). If a source has an activity of \( 3.7 \times 10^{10} \text{ Bq} \), express this activity using the prefix for \( 10^9 \) and the correct symbol.

A laser produces a beam with a power of \( 5.0 \text{ mW} \). What is this power expressed in terms of SI base units?

A high-power microwave pulse has an intensity of \( 4.5 \text{ GW m}^{-2} \). What is this intensity expressed in SI base units?

Identify the power of ten associated with the SI prefix tera (T).

A light-year is the distance light travels in a vacuum in one year (\( 3.15 \times 10^7\text{ s} \)). Calculate the value of 1 light-year in petametres (Pm).
(Speed of light \( c = 3.00 \times 10^8\text{ m s}^{-1} \))

A specific material is cooled to a temperature of \( 4.2\text{ K} \). Which SI physical quantity does the kelvin (K) measure?

A student uses a micrometer to measure the diameter of a uniform metal wire and obtains a value of \( 0.42 \text{ mm} \).
(a) Express the diameter of the wire in meters \(\text{(m)}\) using scientific notation.
(b) The wire has a length of \( 2.50 \text{ m} \). Convert this length into millimeters \(\text{(mm)}\).
(c) If the density of the metal is \( 8.9 \times 10^3 \text{ kg m}^{-3} \), calculate the mass of the wire in grams \(\text{(g)}\).

Newton's law of universal gravitation is given by \( F = \frac{Gm_1m_2}{r^2} \).
(a) Rearrange the formula to make the gravitational constant \( G \) the subject.
(b) Determine the SI base units of \( G \).
(c) A specific measurement for \( G \) is \( 6.67 \times 10^{-11} \text{ N m}^2 \text{ kg}^{-2} \). Convert this value into a form that uses the prefix pico- (p) for the numerical part while keeping the standard units.