Question

1. which statement describes the speed of gamma rays to the speed of infrared radiation when they travel through a vacuum?

a) gamma rays travel faster than infrared radiation.
b) infrared radiation travels faster than gamma rays.
c) gamma rays and infrared radiation travel at the same speed.
d) the speed of both gamma rays and infrared radiation constantly change.

1. which wave has a shorter wavelength than visible light?

a) infrared
b) radio
c) ultraviolet
d) microwave

1. which wave is most likely to cause damage to human cells due to its energy:

a) radio
b) microwave
c) ultraviolet
d) gamma

1. which wavelength is in the infrared range of the electromagnetic spectrum?

a) 100 nm
b) 100 mm
c) 100 m
d) 100 μm

Explanation:

1. All electromagnetic waves (gamma rays and infrared are part of it) travel at the speed of light \(c = 3\times10^{8}\ m/s\) in vacuum.
2. In the electromagnetic spectrum, the order of increasing wavelength is: gamma rays < X - rays < ultraviolet < visible light < infrared < microwaves < radio waves. So ultraviolet has shorter wavelength than visible light.
3. Gamma rays have the highest energy among the given options (due to their high frequency and short wavelength, \(E = h

u=\frac{hc}{\lambda}\), where \(h\) is Planck's constant, \(
u\) is frequency, \(c\) is speed of light and \(\lambda\) is wavelength). High - energy gamma rays can ionize atoms in human cells and cause damage.

1. The infrared range of the electromagnetic spectrum has wavelengths in the range of approximately \(700\ nm - 1\ mm\). \(1\ \mu m=10^{- 6}\ m\), \(1\ nm = 10^{-9}\ m\), \(1\ mm=10^{-3}\ m\). \(100\ \mu m = 100\times10^{-6}\ m=10^{-4}\ m\), \(100\ nm=100\times10^{-9}\ m = 10^{-7}\ m\), \(100\ mm = 0.1\ m\), \(100\ m\) is much larger. So \(100\ \mu m\) is in the infrared range.

Answer:

1. c) Gamma rays and infrared radiation travel at the same speed.
2. c) ultraviolet
3. d) gamma
4. d) 100 μm