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
55°θ₂ = ?crown glass, n1​ = 1.50flint glass, n2​ = 1.62

A light ray in crown glass (n = 1.50) strikes a flat boundary with flint glass (n = 1.62) at 55° to the normal. Find the angle of refraction θ2, measured from the normal.

n1 = 1.50n2 = 1.62θ1 = 55°
θ2 = °
2.Easy
PI = 1 × 10⁻⁷ W/m²

The sound intensity near a classroom is 1 × 10⁻⁷ W/m². Find the sound intensity level β in decibels.

I = 1 × 10⁻⁷ W/m²I0 = 10⁻¹² W/m²
β = dB
3.Medium
30°90°n1​ = ?ethanol, n2​ = 1.36

Light inside a transparent block is totally reflected at the boundary with ethanol (n = 1.36) for every angle of incidence above 30°. Find the refractive index n1 of the block.

θc = 30°n2 = 1.36
n1 =
4.Medium
FFdo​ = 10 cmf = 30 cm

An object stands 10 cm in front of a thin converging lens with a focal length of 30 cm. Find the magnification m (negative for an inverted image).

do = 10 cmf = 30 cm
m =
5.Hard
λ = 600 nmd = 0.25 mmL = 3 my = ?

Light of wavelength 600 nm falls on two slits 0.25 mm apart. The screen is 3 m away. Find the distance y5 from the central bright fringe to bright fringe number 5.

λ = 600 nmd = 0.25 mmL = 3 mm = 5
y5 = mm
6.Hard
Fdo​ = 15 cmR = 30 cm

An object is 15 cm in front of a convex mirror with a radius of curvature of 30 cm. Find the image distance di, positive for an image in front of the mirror (real) and negative for one behind it (virtual).

do = 15 cmR = 30 cm
di = cm

Answer key

  1. 1. θ2 = 49.33 °
  2. 2. β = 50 dB
  3. 3. n1 = 2.72
  4. 4. m = 1.5
  5. 5. y5 = 36 mm
  6. 6. di = −7.5 cm

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