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 = ?v = 3.00 × 10⁸ m/sf = 102.3 MHz

A radio wave has a frequency of 102.3 MHz and travels at 3.00 × 10⁸ m/s. Find its wavelength λ.

f = 102.3 MHzv = 3.00 × 10⁸ m/s
λ = m
2.Easy
v = ?

Find the speed v of light in ethanol, which has a refractive index of 1.36.

n = 1.36c = 3.00 × 10⁸ m/s
v = m/s
3.Medium
SO20 m/sf = 1000 Hz

An observer moves at 20 m/s away from a stationary source of 1000 Hz. The speed of sound is 343 m/s. Find the frequency f′ that the observer hears.

f = 1000 Hzv = 343 m/svo = 20 m/s
f′ = Hz
4.Medium
L = 0.5 mn = 2

A string fixed at both ends is 0.5 m long; waves travel on it at 100 m/s. Find the frequency f2 of its harmonic number 2.

v = 100 m/sn = 2L = 0.5 m
f2 = Hz
5.Hard
λ = 480 nmd = 0.1 mmL = 1.2 my = ?

Light of wavelength 480 nm falls on two slits 0.1 mm apart. The screen is 1.2 m away. Find the distance y1 from the central bright fringe to bright fringe number 1.

λ = 480 nmd = 0.1 mmL = 1.2 mm = 1
y1 = mm
6.Hard
λ = ?45°

A grating with 1200 lines per millimetre shows the order-1 maximum of a spectral line at 45° from the straight-through direction. Find the wavelength λ of the line.

N = 1200 mm⁻¹θ1 = 45°m = 1
λ = nm

Answer key

  1. 1. λ = 2.933 m
  2. 2. v = 2.206 × 10⁸ m/s
  3. 3. f′ = 941.7 Hz
  4. 4. f2 = 200 Hz
  5. 5. y1 = 5.76 mm
  6. 6. λ = 589.3 nm

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