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
v = ?

Find the speed v of light in crown glass, which has a refractive index of 1.50.

n = 1.50c = 3.00 × 10⁸ m/s
v = m/s
2.Easy
λ = ?v = 340 m/sf = 1 kHz

A sound wave in air has a frequency of 1 kHz and travels at 340 m/s. Find its wavelength λ.

f = 1 kHzv = 340 m/s
λ = m
3.Medium
L = 0.65 mn = 3

A pipe closed at one end is 0.65 m long. The speed of sound is 343 m/s. Find the frequency f3 of its harmonic number 3.

v = 343 m/sn = 3L = 0.65 m
f3 = Hz
4.Medium
L = 0.8 mn = 1

A pipe closed at one end is 0.8 m long. The speed of sound is 343 m/s. Find the frequency f1 of its fundamental (first harmonic).

v = 343 m/sn = 1L = 0.8 m
f1 = Hz
5.Hard
λ = ?46.1°

A grating with 1200 lines per millimetre shows the order-1 maximum of a spectral line at 46.1° from the straight-through direction. Find the wavelength λ of the line.

N = 1200 mm⁻¹θ1 = 46.1°m = 1
λ = nm
6.Hard
λ = 500 nmθ

A diffraction grating has 200 lines per millimetre. Light of wavelength 500 nm falls on it at right angles. What is the highest order mmax of bright maximum that can be seen?

N = 200 mm⁻¹λ = 500 nm
mmax =

Answer key

  1. 1. v = 2 × 10⁸ m/s
  2. 2. λ = 0.34 m
  3. 3. f3 = 395.8 Hz
  4. 4. f1 = 107.2 Hz
  5. 5. λ = 600.5 nm
  6. 6. mmax = 9

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