Question 1

A red light has a wavelength ($\lambda$) of 625 nm. What is its frequency ($
u$) in s$^{-1}$? Use $c = 2.99792458 	imes 10^8$ m/s.

Accepted Answer

$4.80 	imes 10^{14}$ s$^{-1}$

Question 2

Calculate the wavelength in nanometers of the light emitted by a barcode scanner that has a frequency of 462 THz. ($1 	ext{ THz} = 1 	imes 10^{12}$ Hz, $c = 2.99792458 	imes 10^8$ m/s).

Accepted Answer

$649$ nm

Question 3

Which of the following correctly describes constructive interference between two waves?

Accepted Answer

The amplitudes of the two waves add together, resulting in a wave with greater amplitude.

Question 4

Which type of electromagnetic radiation has the highest frequency?

Accepted Answer

Gamma rays

Question 5

Given the speed of light $c = 2.99792458 	imes 10^8$ m/s, what is the wavelength ($\lambda$) of electromagnetic radiation with a frequency ($
u$) of $5.00 	imes 10^{14}$ Hz?

Accepted Answer

$600$ nm

Question 6

A microwave oven uses radiation with a wavelength of $12.2$ cm. What is the frequency of this radiation? ($c = 2.99792458 	imes 10^8$ m/s)

Accepted Answer

$2.46 	imes 10^9$ Hz

Question 7

Which of the following statements about electromagnetic radiation is correct?

Accepted Answer

As the frequency of electromagnetic radiation increases, its energy increases.

Question 8

A green laser pointer emits light at a wavelength of $532$ nm. What is the energy of one photon of this light? ($h = 6.626 	imes 10^{-34}$ J·s, $c = 2.99792458 	imes 10^8$ m/s)

Accepted Answer

$3.74 	imes 10^{-19}$ J

Question 9

Which of the following best explains why X-rays are used in medical imaging?

Accepted Answer

X-rays have high energy and short wavelengths, allowing them to penetrate tissues and produce images of internal structures.

Question 10

If two waves of equal amplitude and frequency meet in phase, what type of interference occurs and what is the resulting amplitude?

Accepted Answer

Constructive interference; amplitude is doubled.

Question 11

Which of the following electromagnetic waves has the longest wavelength?

Accepted Answer

Microwaves

Question 12

A hospital uses infrared radiation to keep newborns warm. Which property of infrared radiation makes it suitable for this purpose?

Accepted Answer

Infrared radiation transfers energy as heat, which can be absorbed by the skin.

Question 13

Which equation correctly relates the speed of light ($c$), wavelength ($\lambda$), and frequency ($
u$)?

Accepted Answer

$c = \lambda 
u$

Question 14

A scientist observes destructive interference between two sound waves. What must be true about the waves?

Accepted Answer

The waves have equal amplitude and are exactly out of phase.

Question 15

Which of the following is the correct order of electromagnetic radiation from lowest to highest frequency?

Accepted Answer

Microwaves, green light, gamma rays

Question 16

A barcode scanner emits light at a frequency of $4.62 	imes 10^{14}$ Hz. What is the energy of one photon of this light? ($h = 6.626 	imes 10^{-34}$ J·s)

Accepted Answer

$3.06 	imes 10^{-19}$ J

Question 17

Which of the following is a common misconception about the speed of electromagnetic waves in a vacuum?

Accepted Answer

Different types of electromagnetic waves travel at different speeds in a vacuum.

Question 18

A student claims that green light has more energy per photon than microwaves. Is this statement correct? Why?

Accepted Answer

Yes, because green light has a higher frequency than microwaves.

Question 19

Which of the following best describes the relationship between wavelength and frequency for electromagnetic waves?

Accepted Answer

As wavelength increases, frequency decreases.

Question 20

A medical imaging device uses electromagnetic radiation with a frequency of $1.00 	imes 10^{18}$ Hz. What type of radiation is this most likely to be?

Accepted Answer

X-rays

Electromagnetic Radiation: Frequency, Wavelength, and Interference

Study Guide - Practice Questions

Study Guide - Flashcards