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
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
Pβ = 55 dB

The sound intensity level at a point is 55 dB. Find the sound intensity I.

β = 55 dBI0 = 10⁻¹² W/m²
I = µW/m²
3.Medium
L = 0.8 mn = 7

A pipe closed at one end is 0.8 m long. The speed of sound is 343 m/s. Find the frequency f7 of its harmonic number 7.

v = 343 m/sn = 7L = 0.8 m
f7 = Hz
4.Medium
L = 0.75 mn = 3

A pipe closed at one end is 0.75 m long. The speed of sound is 343 m/s. Find the frequency f3 of its harmonic number 3.

v = 343 m/sn = 3L = 0.75 m
f3 = Hz
5.Hard
λ = 600 nmθ

A diffraction grating has 500 lines per millimetre. Light of wavelength 600 nm falls on it at right angles. What is the highest order mmax of bright maximum that can be seen?

N = 500 mm⁻¹λ = 600 nm
mmax =
6.Hard
λ = 600 nmd = 0.25 mmL = 1.5 my = ?

Light of wavelength 600 nm falls on two slits 0.25 mm apart. The screen is 1.5 m away. Find the distance y4 from the central bright fringe to bright fringe number 4.

λ = 600 nmd = 0.25 mmL = 1.5 mm = 4
y4 = mm

Answer key

  1. 1. λ = 2.933 m
  2. 2. I = 0.3162 µW/m²
  3. 3. f7 = 750.3 Hz
  4. 4. f3 = 343 Hz
  5. 5. mmax = 3
  6. 6. y4 = 14.4 mm

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