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
L = 0.8 m

A string of length 0.8 m and mass 4 g carries transverse waves at 223.6 m/s. Find the tension T in the string.

L = 0.8 mm = 4 gv = 223.6 m/s
T = N
2.Easy
L = 2 m

A string of length 2 m and mass 10 g is stretched with a tension of 80 N. Find the speed v of transverse waves on it.

L = 2 mm = 10 gT = 80 N
v = m/s
3.Medium
80 dB?2 m6 m

A small source sends sound equally in all directions. The level is 80 dB at 2 m from it. Find the level β2 at 6 m, ignoring absorption and reflections.

β1 = 80 dBr1 = 2 mr2 = 6 m
β2 = dB
4.Medium
P3 × 72 dB

One machine gives a sound level of 72 dB at a certain point. Find the level β at that point when 3 identical machines run at the same time (incoherent sources).

β1 = 72 dBn = 3
β = dB
5.Hard
f1​ = 12 cmf2​ = 15 cm15 cm25 cm

Two thin lenses share an axis, 25 cm apart: lens 1 with f₁ = 12 cm and lens 2 with f₂ = 15 cm. An object stands 15 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 = 12 cmf2 = 15 cms = 25 cmdo = 15 cm
di2 = cm
6.Hard
λ = 500 nma = 0.1 mm

Light of wavelength 500 nm passes through a single slit 0.1 mm wide. Find the angle θ2 of dark fringe number 2 from the straight-through direction.

λ = 500 nma = 0.1 mmm = 2
θ2 = °

Answer key

  1. 1. T = 250 N
  2. 2. v = 126.5 m/s
  3. 3. β2 = 70.46 dB
  4. 4. β = 76.77 dB
  5. 5. di2 = 10.5 cm
  6. 6. θ2 = 0.573 °

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