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
v = 2.04 × 10⁸ m/s

Light travels at 2.04 × 10⁸ m/s in a transparent material. Find its refractive index n.

v = 2.04 × 10⁸ m/sc = 3.00 × 10⁸ m/s
n =
2.Easy
L = 1.2 m

A string of length 1.2 m and mass 3 g is stretched with a tension of 200 N. Find the speed v of transverse waves on it.

L = 1.2 mm = 3 gT = 200 N
v = m/s
3.Medium
Pβ = ?r = 2 m

A small loudspeaker radiates 0.05 W of sound power equally in all directions. Find the sound intensity level β at 2 m.

P = 0.05 Wr = 2 mI0 = 10⁻¹² W/m²
β = dB
4.Medium
θc = ?90°diamond, n1​ = 2.42acrylic, n2​ = 1.49

Light travels in diamond (n = 2.42) towards a flat boundary with acrylic (n = 1.49). Find the critical angle θc beyond which it is totally reflected.

n1 = 2.42n2 = 1.49
θc = °
5.Hard
λ = 500 nmd = 0.15 mmL = 1.5 my = ?

Light of wavelength 500 nm falls on two slits 0.15 mm apart. The screen is 1.5 m away. Find the distance y3 from the central bright fringe to bright fringe number 3.

λ = 500 nmd = 0.15 mmL = 1.5 mm = 3
y3 = mm
6.Hard
Fdo​ = 5 cmR = 16 cm

An object is 5 cm in front of a concave mirror with a radius of curvature of 16 cm. Find the magnification m (negative for an inverted image).

do = 5 cmR = 16 cm
m =

Answer key

  1. 1. n = 1.471
  2. 2. v = 282.8 m/s
  3. 3. β = 89.98 dB
  4. 4. θc = 38 °
  5. 5. y3 = 15 mm
  6. 6. m = 2.667

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