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
Pβ = 65 dB

The sound intensity level at a point is 65 dB. Find the sound intensity I.

β = 65 dBI0 = 10⁻¹² W/m²
I = µW/m²
2.Easy
λ = ?v = 343 m/sf = 1 kHz

A sound wave in air has a frequency of 1 kHz and travels at 343 m/s. Find its wavelength λ.

f = 1 kHzv = 343 m/s
λ = m
3.Medium
L = 0.4 mn = 5

A pipe open at both ends is 0.4 m long. The speed of sound is 343 m/s. Find the frequency f5 of its harmonic number 5.

v = 343 m/sn = 5L = 0.4 m
f5 = Hz
4.Medium
θc = ?90°diamond, n1​ = 2.42crown glass, n2​ = 1.50

Light travels in diamond (n = 2.42) towards a flat boundary with crown glass (n = 1.50). Find the critical angle θc beyond which it is totally reflected.

n1 = 2.42n2 = 1.50
θc = °
5.Hard
λ = 532 nmd = 0.4 mmL = 1.5 my = ?

Light of wavelength 532 nm falls on two slits 0.4 mm apart. The screen is 1.5 m away. Find the distance y3 from the central bright fringe to bright fringe number 3.

λ = 532 nmd = 0.4 mmL = 1.5 mm = 3
y3 = mm
6.Hard
λ = ?d = 0.5 mmL = 1.2 m7.596 mm

Two slits 0.5 mm apart are lit with monochromatic light. On a screen 1.2 m away, bright fringe number 5 lies 7.596 mm from the central fringe. Find the wavelength λ.

d = 0.5 mmL = 1.2 my5 = 7.596 mmm = 5
λ = nm

Answer key

  1. 1. I = 3.162 µW/m²
  2. 2. λ = 0.343 m
  3. 3. f5 = 2144 Hz
  4. 4. θc = 38.3 °
  5. 5. y3 = 5.985 mm
  6. 6. λ = 633 nm

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