Waves, sound & optics worksheet with answers

Free printable Waves, sound & optics worksheet: 6 problems from easy to exam level, with an answer key. Print it or save it as a PDF.

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1.Easy
λ = ?v = 340 m/sf = 2 kHz

A sound wave in air has a frequency of 2 kHz and travels at 340 m/s. Find its wavelength λ.

f = 2 kHzv = 340 m/s
λ = m
2.Easy
v = ?

Find the speed v of light in ethanol, which has a refractive index of 1.36.

n = 1.36c = 3.00 × 10⁸ m/s
v = m/s
3.Medium
S15 m/sOf = 500 Hz

A source of 500 Hz moves at 15 m/s away from a stationary observer. The speed of sound is 343 m/s. Find the frequency f′ that the observer hears.

f = 500 Hzv = 343 m/svs = 15 m/s
f′ = Hz
4.Medium
θc = ?90°diamond, n1​ = 2.42water, n2​ = 1.33

Light travels in diamond (n = 2.42) towards a flat boundary with water (n = 1.33). Find the critical angle θc beyond which it is totally reflected.

n1 = 2.42n2 = 1.33
θc = °
5.Hard
λ = 550 nmθ

A diffraction grating has 100 lines per millimetre. Light of wavelength 550 nm falls on it at right angles. What is the highest order mmax of bright maximum that can be seen?

N = 100 mm⁻¹λ = 550 nm
mmax =
6.Hard
λ = 600 nma = 0.1 mm

Light of wavelength 600 nm passes through a single slit 0.1 mm wide. Find the angle θ1 of dark fringe number 1 from the straight-through direction.

λ = 600 nma = 0.1 mmm = 1
θ1 = °

Answer key

  1. 1. λ = 0.17 m
  2. 2. v = 2.206 × 10⁸ m/s
  3. 3. f′ = 479.1 Hz
  4. 4. θc = 33.34 °
  5. 5. mmax = 18
  6. 6. θ1 = 0.3438 °

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