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
L = 2.5 m

A string of length 2.5 m and mass 3 g carries transverse waves at 182.6 m/s. Find the tension T in the string.

L = 2.5 mm = 3 gv = 182.6 m/s
T = N
2.Easy
λ = ?v = 3.00 × 10⁸ m/sf = 100 MHz

A radio wave has a frequency of 100 MHz and travels at 3.00 × 10⁸ m/s. Find its wavelength λ.

f = 100 MHzv = 3.00 × 10⁸ m/s
λ = m
3.Medium
FFdo​ = 50 cmf = −5 cm

An object stands 50 cm in front of a thin diverging lens with a focal length of 5 cm. Find the image distance di. Use the sign convention 1/f = 1/do + 1/di (f < 0 for a diverging lens, di < 0 for a virtual image).

do = 50 cmf = −5 cm
di = cm
4.Medium
FFdo​ = 15 cmf = −25 cm

An object stands 15 cm in front of a thin diverging lens with a focal length of 25 cm. Find the image distance di. Use the sign convention 1/f = 1/do + 1/di (f < 0 for a diverging lens, di < 0 for a virtual image).

do = 15 cmf = −25 cm
di = cm
5.Hard
λ = 656 nmθ

A diffraction grating has 1200 lines per millimetre. Light of wavelength 656 nm falls on it at right angles. What is the highest order mmax of bright maximum that can be seen?

N = 1200 mm⁻¹λ = 656 nm
mmax =
6.Hard
λ = ?40.4°

A grating with 800 lines per millimetre shows the order-2 maximum of a spectral line at 40.4° from the straight-through direction. Find the wavelength λ of the line.

N = 800 mm⁻¹θ2 = 40.4°m = 2
λ = nm

Answer key

  1. 1. T = 40.01 N
  2. 2. λ = 3 m
  3. 3. di = −4.545 cm
  4. 4. di = −9.375 cm
  5. 5. mmax = 1
  6. 6. λ = 405.1 nm

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