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 = 343 m/sf = 50 Hz

A sound wave in air has a frequency of 50 Hz and travels at 343 m/s. Find its wavelength λ.

f = 50 Hzv = 343 m/s
λ = m
2.Easy
L = 1.5 m

A string of length 1.5 m and mass 10 g is stretched with a tension of 100 N. Find the speed v of transverse waves on it.

L = 1.5 mm = 10 gT = 100 N
v = m/s
3.Medium
FF2 cmdo​ = 50 cmf = −8 cm

An object 2 cm tall stands 50 cm in front of a thin diverging lens with a focal length of 8 cm. Find the image height hi (negative for an inverted image).

ho = 2 cmdo = 50 cmf = −8 cm
hi = cm
4.Medium
P2 × 72 dB

One machine gives a sound level of 72 dB at a certain point. Find the level β at that point when 2 identical machines run at the same time (incoherent sources).

β1 = 72 dBn = 2
β = dB
5.Hard
λ = 633 nmθ3​ = ?

Light of wavelength 633 nm falls at right angles on a grating with 300 lines per millimetre. Find the angle θ3 of the order-3 maximum.

N = 300 mm⁻¹λ = 633 nmm = 3
θ3 = °
6.Hard
Fdo​ = 6 cmR = 24 cm

An object is 6 cm in front of a convex mirror with a radius of curvature of 24 cm. Find the magnification m (negative for an inverted image).

do = 6 cmR = 24 cm
m =

Answer key

  1. 1. λ = 6.86 m
  2. 2. v = 122.5 m/s
  3. 3. hi = 0.2759 cm
  4. 4. β = 75.01 dB
  5. 5. θ3 = 34.73 °
  6. 6. m = 0.6667

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