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
70°θ₂ = ?crown glass, n1​ = 1.50diamond, n2​ = 2.42

A light ray in crown glass (n = 1.50) strikes a flat boundary with diamond (n = 2.42) at 70° to the normal. Find the angle of refraction θ2, measured from the normal.

n1 = 1.50n2 = 2.42θ1 = 70°
θ2 = °
2.Easy
λ = 8 mv = ?f = 0.25 Hz

A water wave has a frequency of 0.25 Hz and a wavelength of 8 m. Find its speed v.

f = 0.25 Hzλ = 8 m
v = m/s
3.Medium
FF1 cmdo​ = 40 cmf = 30 cm

An object 1 cm tall stands 40 cm in front of a thin converging lens with a focal length of 30 cm. Find the image height hi (negative for an inverted image).

ho = 1 cmdo = 40 cmf = 30 cm
hi = cm
4.Medium
100 dB?5 m20 m

A small source sends sound equally in all directions. The level is 100 dB at 5 m from it. Find the level β2 at 20 m, ignoring absorption and reflections.

β1 = 100 dBr1 = 5 mr2 = 20 m
β2 = dB
5.Hard
SO25 m/sf = 20 kHz

A sensor at rest sends ultrasound of 20 kHz towards a car that moves away at 25 m/s and mixes the echo with the emitted signal. Find the beat frequency fb (speed of sound 343 m/s).

f = 20 kHzu = 25 m/sv = 343 m/s
fb = Hz
6.Hard
λ = 650 nmd = 0.5 mmL = 3 my = ?

Light of wavelength 650 nm falls on two slits 0.5 mm apart. The screen is 3 m away. Find the distance y3 from the central bright fringe to bright fringe number 3.

λ = 650 nmd = 0.5 mmL = 3 mm = 3
y3 = mm

Answer key

  1. 1. θ2 = 35.62 °
  2. 2. v = 2 m/s
  3. 3. hi = −3 cm
  4. 4. β2 = 87.96 dB
  5. 5. fb = 2717 Hz
  6. 6. y3 = 11.7 mm

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