Light and Sound

Name the process that happens to the sound wave as it passes into the cooler region.

Explain, with reference to the speed of sound, why the direction of the wave changes.

Describe one real-life example where this process makes sounds easier to hear over long distances.

State whether light and sound waves are transverse or longitudinal. Give one example of how each is used in daily life.

Sound is reflected off a flat wall and returns to a listener as an echo. Light is reflected from a mirror.

Draw and label a simple ray diagram to show the path of a ray of light entering and leaving a rectangular glass block. Mark the normal, angle of incidence and angle of refraction.

The student claps blocks of wood at a known distance from a wall. The time between clapping and hearing the echo is measured as 2.0 s, and the distance to the wall is 170 m. Calculate the speed of sound in air.

Explain how total internal reflection allows light to travel through an optical fibre without escaping.

Doctors use optical fibres in endoscopes to see inside the body. State one reason why this is better than traditional surgery. Give one way sound is used in medicine.

The student sets up a sound wave with a frequency of 100 Hz and speed 340 m/s. Calculate its wavelength.

On an oscilloscope, the student sees two traces: - Trace A has high frequency and large amplitude. - Trace B has low frequency and small amplitude. Explain the difference in pitch and loudness between the two traces.

Draw a ray diagram to show the path of a ray of light entering a rectangular glass block from air at an angle. Show the angles of incidence and refraction.

The angle of incidence is measured as 45° and the angle of refraction is 28°. Calculate the refractive index of the glass.

Describe how the speed of sound in air can be measured in a school lab, using the reflection of sound. Name the piece of equipment you could use to display a sound wave.

Explain why total internal reflection occurs inside an optical fibre and draw a labelled diagram to illustrate it.

State one medical and one communication use of optical fibres.

A certain type of glass has a refractive index of 1.56. Calculate its critical angle for total internal reflection.

Complete the ray diagram below for a ray passing from air into a glass block and emerging on the other side. Draw the path through the block, marking the normals, angles of incidence and refraction.

A ship uses echo sounding (sonar) to measure ocean depth. If the sound pulse returns after 3.0 s and the speed of sound in seawater is 1500 m/s, calculate the depth of the ocean.

Compare the laws of reflection for light and sound. Give one difference in how each wave behaves when it meets a surface.

State whether light and sound are transverse or longitudinal waves respectively. Give one piece of evidence for your answer in each case.

A sound wave has a frequency of 440 Hz and travels at 340 m/s in air. Calculate its wavelength.

State the range of frequencies the average person can hear. Describe how loudness and pitch are represented on an oscilloscope trace of a sound wave.

Describe and explain what happens to a ray of light inside a prism when it strikes the surface at an angle greater than the critical angle. Draw a labelled diagram to support your answer.

Calculate the angle of refraction if a ray of light enters glass from air at 35° and the refractive index of glass is 1.52.

Binoculars use prisms for total internal reflection, but sound waves cannot be 'bent' this way. Suggest one reason for this difference.