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 = 2.78 mv = 3.00 × 10⁸ m/sf = ?

A radio wave travels at 3.00 × 10⁸ m/s with a wavelength of 2.78 m. Find its frequency f.

λ = 2.78 mv = 3.00 × 10⁸ m/s
f = MHz
2.Easy
λ = ?

Light with a wavelength of 405 nm in vacuum enters flint glass (n = 1.62). Find its wavelength λ inside the material.

n = 1.62λ0 = 405 nm
λ = nm
3.Medium
L = 1 mn = 1

A pipe open at both ends is 1 m long. The speed of sound is 343 m/s. Find the frequency f1 of its fundamental (first harmonic).

v = 343 m/sn = 1L = 1 m
f1 = Hz
4.Medium
L = ?n = 5

A string fixed at both ends must have its harmonic number 5 at 500 Hz; waves travel on it at 240 m/s. Find its length L.

v = 240 m/sn = 5f5 = 500 Hz
L = m
5.Hard
λ = 633 nmθ

A diffraction grating has 100 lines per millimetre. Light of wavelength 633 nm falls on it at right angles. What is the highest order mmax of bright maximum that can be seen?

N = 100 mm⁻¹λ = 633 nm
mmax =
6.Hard
λ = 600 nmθ2​ = ?

Light of wavelength 600 nm falls at right angles on a grating with 800 lines per millimetre. Find the angle θ2 of the order-2 maximum.

N = 800 mm⁻¹λ = 600 nmm = 2
θ2 = °

Answer key

  1. 1. f = 107.9 MHz
  2. 2. λ = 250 nm
  3. 3. f1 = 171.5 Hz
  4. 4. L = 1.2 m
  5. 5. mmax = 15
  6. 6. θ2 = 73.74 °

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