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.

New worksheetPractise online with hints

For teachers: free to print, copy and use in class. Every new worksheet has new values and its own answer key. A link to ExamProblems on your course page is appreciated.

Name: ____________________   Date: ____________

1.Easy
λ = 7.5 mv = 3 m/sf = ?

A water wave travels at 3 m/s with a wavelength of 7.5 m. Find its frequency f.

λ = 7.5 mv = 3 m/s
f = Hz
2.Easy
v = ?

Find the speed v of light in glycerol, which has a refractive index of 1.47.

n = 1.47c = 3.00 × 10⁸ m/s
v = m/s
3.Medium
45°90°n1​ = ?water, n2​ = 1.33

Light inside a transparent block is totally reflected at the boundary with water (n = 1.33) for every angle of incidence above 45°. Find the refractive index n1 of the block.

θc = 45°n2 = 1.33
n1 =
4.Medium
θc = ?90°crown glass, n1​ = 1.50ethanol, n2​ = 1.36

Light travels in crown glass (n = 1.50) towards a flat boundary with ethanol (n = 1.36). Find the critical angle θc beyond which it is totally reflected.

n1 = 1.50n2 = 1.36
θc = °
5.Hard
f1​ = 8 cmf2​ = 20 cm18 cm10 cm

Two thin lenses share an axis, 10 cm apart: lens 1 with f₁ = 8 cm and lens 2 with f₂ = 20 cm. An object stands 18 cm in front of lens 1. Find the position di2 of the final image measured from lens 2 (positive beyond lens 2, real-is-positive convention).

f1 = 8 cmf2 = 20 cms = 10 cmdo = 18 cm
di2 = cm
6.Hard
λ = 500 nma = 0.15 mmL = 3 m

Light of wavelength 500 nm passes through a single slit 0.15 mm wide. Find the width w of the central bright maximum on a screen 3 m away (between the first dark fringes on either side).

λ = 500 nma = 0.15 mmL = 3 m
w = mm

Answer key

  1. 1. f = 0.4 Hz
  2. 2. v = 2.041 × 10⁸ m/s
  3. 3. n1 = 1.881
  4. 4. θc = 65.05 °
  5. 5. di2 = 3.607 cm
  6. 6. w = 20 mm

Full step-by-step solutions: practise this topic on examproblems.com.