Reflection, refraction and diffraction of waves
Grade 11 Science Worksheet
Circle the best answer, or write your answer on the line.
A ray in air (n = 1) meets glass (n = 1.5) at 50° from the normal. What is its angle from the normal in glass, to the nearest degree, Bo?
A ray in water (n = 1.33) meets air (n = 1) at 25° from the normal. What is its angle from the normal in air, to the nearest degree, Esme?
A 1,000 Hz sound (wavelength 0.34 m) and green light (wavelength 500 nm) both pass through a 1.0 m wide doorway. What do you notice behind the doorway, Jun?
- The sound spreads widely; the light barely spreads
- Neither spreads, because the doorway is wider than both wavelengths
- The light spreads widely behind the doorway; the sound hardly spreads
- Both spread by about the same amount, since both pass through the same doorway
Light of wavelength 500 nm passes through a single slit 2.0 μm wide. The first dark band is at sin θ = λ ÷ width. At what angle is it, Kira?
- 29°
- 0.25°
- 76°
- 14°
Radio waves of wavelength 3 m bend round a hill 50 m wide, but light of wavelength 500 nm does not. Which explanation fits, Luz?
- Light is too fast to bend round a hill, however wide the hill is
- Radio waves carry more energy than light, so they push round the hill
- Radio waves are mechanical waves, which can bend round solid hills in a way light cannot
- The hill is only about 17 times the radio wavelength, but millions of times the light's
A ray inside glass (n = 1.50) hits the glass-air surface at 45° from the normal. The critical angle is 41.8°. What happens, Milo?
- All the light reflects back into the glass
- Half reflects and half passes into air
- It passes into air, bending away from the normal
- It passes into air, bending toward the normal
A ray inside the same glass (n = 1.50, critical angle 41.8°) hits the glass-air surface at 38° from the normal. What happens, Noah?
- Most of it passes into air, bending away from the normal
- Everything reflects back into the glass, since the surface acts like a mirror
- It passes into air without bending, since 38° is a small angle
- It passes into air, bending toward the normal
An optical fiber has a core with n = 1.48 and cladding with n = 1.46. What is the critical angle at the core-cladding boundary, from the normal, Pia?
- 47.5°
- 9.4°
- 80.6°
- 42.5°
Sound in air meets the surface of calm water, where sound is faster. How does the sound that enters the water bend, Ren?
- Toward the normal, like light entering glass
- It does not bend, because sound is not light
- Away from the normal
- Along the surface of the water
Sound in 20 °C air (343.3 m/s) meets calm fresh water (1481 m/s). Above what angle from the normal is it totally reflected, Tala?
- About 77°
- About 4.3°
- About 13°
- About 0.23°