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 worksheet Practise 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

A sound wave in water has a frequency of 100 Hz and travels at 1480 m/s. Find its wavelength λ.

f = 100 Hzv = 1480 m/s

λ = m

2.Easy

A string of length 2.5 m and mass 8 g carries transverse waves at 136.9 m/s. Find the tension T in the string.

L = 2.5 mm = 8 gv = 136.9 m/s

T = N

3.Medium

Light inside a transparent block is totally reflected at the boundary with water (n = 1.33) for every angle of incidence above 40°. Find the refractive index n₁ of the block.

θ_c = 40°n₂ = 1.33

n₁ =

4.Medium

Light travels in diamond (n = 2.42) towards a flat boundary with crown glass (n = 1.50). Find the critical angle θ_c beyond which it is totally reflected.

n₁ = 2.42n₂ = 1.50

θ_c = °

5.Hard

Two thin lenses share an axis, 50 cm apart: lens 1 with f₁ = 10 cm and lens 2 with f₂ = −10 cm. An object stands 40 cm in front of lens 1. Find the position d_i2 of the final image measured from lens 2 (positive beyond lens 2, real-is-positive convention).

f₁ = 10 cmf₂ = −10 cms = 50 cmd_o = 40 cm

d_i2 = cm

6.Hard

A parking sensor at rest sends ultrasound of 40 kHz towards a car that approaches at 10 m/s. Find the frequency f″ of the echo received back at the sensor (speed of sound 343 m/s).

f = 40 kHzu = 10 m/sv = 343 m/s

f″ = Hz

Answer key

1. λ = 14.8 m
2. T = 59.97 N
3. n₁ = 2.069
4. θ_c = 38.3 °
5. d_i2 = −7.857 cm
6. f″ = 42402 Hz

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