Questions on Wavelength and Frequency Calculations
20 Multiple-Choice Questions: Wavelength and Frequency Calculations
1. The speed of light in a vacuum is approximately:
A) 2.0 × 10⁸ m/s
B) 1.5 × 10⁶ m/s
C) 3.0 × 10⁸ m/s
D) 6.0 × 10⁸ m/s
E) 3.0 × 10⁶ m/s
2. What is the formula that relates speed of light (c), wavelength (λ), and frequency (ν)?
A) c = λ + ν
B) c = λ – ν
C) c = λ × ν
D) c = λ ÷ ν
E) c = ν² × λ
3. If the frequency of a wave is 6.0 × 10¹⁴ Hz, and the speed of light is 3.0 × 10⁸ m/s, what is the wavelength?
A) 2.0 × 10⁻⁷ m
B) 5.0 × 10⁻⁶ m
C) 3.0 × 10⁻⁷ m
D) 6.0 × 10⁶ m
E) 1.8 × 10²² m
4. A wave has a wavelength of 4.0 × 10⁻⁷ m. What is its frequency? (Use c = 3.0 × 10⁸ m/s)
A) 6.0 × 10¹⁵ Hz
B) 7.5 × 10¹⁴ Hz
C) 2.5 × 10⁸ Hz
D) 1.2 × 10⁵ Hz
E) 4.5 × 10⁷ Hz
5. What happens to wavelength if frequency increases (c is constant)?
A) Increases
B) Decreases
C) Stays the same
D) Becomes zero
E) Doubles
6. Which wave has the highest frequency?
A) Radio wave
B) Microwave
C) Infrared
D) Ultraviolet
E) Gamma ray
7. What are the units of frequency?
A) m/s
B) seconds
C) Hz (s⁻¹)
D) J/kg
E) V/m
8. If a wave has a frequency of 5.0 × 10¹⁴ Hz and travels at 3.0 × 10⁸ m/s, what is the wavelength?
A) 6.0 × 10⁻⁷ m
B) 1.5 × 10⁻⁶ m
C) 5.5 × 10⁻⁷ m
D) 3.0 × 10⁻⁷ m
E) 4.2 × 10⁻⁶ m
9. Frequency and wavelength are:
A) Directly proportional
B) Inversely proportional
C) Not related
D) Equal
E) Always constant
10. What is the wavelength of light with a frequency of 3.75 × 10¹⁴ Hz? (Use c = 3.0 × 10⁸ m/s)
A) 1.25 × 10⁻⁶ m
B) 8.0 × 10⁻⁶ m
C) 7.5 × 10⁻⁷ m
D) 2.25 × 10⁶ m
E) 4.5 × 10⁻⁵ m
11. If wavelength is doubled, what happens to frequency (c is constant)?
A) Doubled
B) Halved
C) Quadrupled
D) Remains unchanged
E) Becomes zero
12. Which of the following correctly describes electromagnetic radiation?
A) It travels faster than light
B) Its frequency is independent of wavelength
C) Its speed is variable in a vacuum
D) It follows the equation c = λν
E) It can’t be measured
13. A wave with frequency 1.0 × 10¹⁵ Hz has what wavelength?
A) 3.0 × 10⁻⁶ m
B) 3.0 × 10⁻⁸ m
C) 3.0 × 10⁻⁷ m
D) 3.0 × 10⁷ m
E) 3.0 × 10³ m
14. What type of wave has the longest wavelength?
A) Ultraviolet
B) Gamma
C) Infrared
D) Microwave
E) Radio
15. The wavelength of red light is approximately:
A) 700 nm
B) 500 nm
C) 300 nm
D) 1500 nm
E) 100 nm
16. As wavelength increases, energy of the wave:
A) Increases
B) Stays the same
C) Decreases
D) Doubles
E) Becomes infinite
17. In which situation would a wave have the lowest frequency?
A) Short wavelength, high energy
B) Long wavelength, low energy
C) Medium wavelength, high speed
D) High wavelength, high energy
E) Short wavelength, low speed
18. If λ = 500 nm, what is the frequency in Hz? (1 nm = 1 × 10⁻⁹ m; c = 3.0 × 10⁸ m/s)
A) 6.0 × 10¹⁴ Hz
B) 1.5 × 10¹² Hz
C) 3.0 × 10¹² Hz
D) 2.0 × 10¹⁵ Hz
E) 4.0 × 10⁶ Hz
19. A light wave has a frequency of 6.0 × 10¹⁴ Hz. What is its energy? Use E = hν, h = 6.63 × 10⁻³⁴ J·s
A) 3.98 × 10⁻¹⁹ J
B) 9.94 × 10⁻²⁰ J
C) 4.25 × 10⁻¹⁶ J
D) 1.23 × 10⁻¹⁷ J
E) 6.00 × 10⁻³⁴ J
20. Which equation represents the relationship between energy and frequency?
A) E = mc²
B) E = h/ν
C) E = hν
D) E = λ/c
E) E = ν²h
Answers with Extended Explanations
1. C – The speed of light in vacuum is 3.0 × 10⁸ m/s.
2. C – The fundamental equation: c = λν.
3. A – λ = c/ν = (3.0×10⁸)/(6.0×10¹⁴) = 5.0 × 10⁻⁷ m.
4. B – ν = c/λ = (3.0×10⁸)/(4.0×10⁻⁷) = 7.5 × 10¹⁴ Hz.
5. B – Frequency and wavelength are inversely proportional.
6. E – Gamma rays have the highest frequencies.
7. C – Frequency is measured in Hertz (Hz) or s⁻¹.
8. A – λ = c/ν = 3.0×10⁸ / 5.0×10¹⁴ = 6.0 × 10⁻⁷ m.
9. B – As one increases, the other decreases (inverse).
10. A – λ = c/ν = 3.0×10⁸ / 3.75×10¹⁴ = 8.0 × 10⁻⁷ m.
11. B – Frequency is halved if wavelength doubles.
12. D – Electromagnetic radiation follows c = λν.
13. C – λ = c/ν = 3.0×10⁸ / 1.0×10¹⁵ = 3.0 × 10⁻⁷ m.
14. E – Radio waves have the longest wavelengths.
15. A – Red light ~700 nm.
16. C – Longer wavelengths = lower energy.
17. B – Low energy, long wavelength → lowest frequency.
18. A – ν = c/λ = 3.0×10⁸ / 5.0×10⁻⁷ = 6.0 × 10¹⁴ Hz.
19. A – E = hν = 6.63×10⁻³⁴ × 6.0×10¹⁴ = 3.98 × 10⁻¹⁹ J.
20. C – Planck’s equation: E = hν.
Share Online!
