Waves

An electric bell is ringing inside a sealed glass jar. A pump slowly removes all the air from the jar. The bell can still be seen vibrating.
What happens to the sound heard outside the jar?

A musician plays the same note on a trumpet twice. The second time it is louder, but the pitch is the same.
How has the sound wave changed?

Which of these sound frequencies can be heard by a person with normal hearing?

Students measure the speed of sound on a playing field. One student fires a starting pistol. A second student stands 400 m away, starts a stopwatch on seeing the smoke from the pistol, and stops it on hearing the bang. The time recorded is 1.18 s.

A ray of light strikes a flat plane mirror. The ray makes an angle of 35° with the surface of the mirror.
What is the angle of reflection?

A student stands 1.5 m in front of a vertical plane mirror and looks at her image.
Which description of the image is correct?

A ray of light in air enters a glass block along the normal (angle of incidence 0°).
What happens to the speed and the direction of the light as it enters the glass?

A narrow beam of white light passes through a triangular glass prism and a spectrum forms on a screen.
Which colour is refracted (deviated) the most?

A student shines a ray of light from air into one face of a rectangular glass block. The angle of incidence is 40°.

Which list shows four regions of the electromagnetic spectrum in order of increasing wavelength?

Which quantity is the same for all electromagnetic waves travelling in a vacuum?

Sealed packs of surgical instruments are sterilised without opening them. Which type of electromagnetic radiation is used?

A firefighter uses a thermal imaging camera to find a person in a smoke-filled room. Which radiation does the camera detect?

Water waves on a lake have a frequency of 2.5 Hz and a wavelength of 0.40 m.
What is the speed of the waves?

Which of these is a longitudinal wave?

A student stands 1.5 m in front of a vertical plane mirror.
What is the distance between the student and the student's image?

A buoy floats in the sea near a harbour. Sea waves pass the buoy and make it rise and fall.

A hospital uses several types of electromagnetic radiation.

A kitchen contains a microwave oven and a television with a remote control.

A dentist uses a small plane mirror to look at the back of a patient's teeth.

A narrow beam of white light from a ray box passes through a triangular glass prism. A band of colours appears on a white screen beyond the prism.

A guitarist plucks a string on an acoustic guitar. A listener a few metres away hears the note.

A buoy rises and falls 15 times in 30 s as ocean waves pass it. The distance between neighbouring crests is 6.0 m. What is the speed of the waves?

Light travelling inside a glass prism meets the glass–air surface. Which pair of conditions is needed for total internal reflection?

Which list shows electromagnetic waves in order of increasing frequency?

A guitar string is plucked gently. The string is then shortened by pressing it against the neck and plucked harder. How do the amplitude and frequency of the new note compare with the first note?

Waves in a harbour move at a steady speed of 2.4 m/s. The distance between one crest and the next crest is 3.0 m.

A ship's radio uses electromagnetic waves of frequency 150 MHz.

Divers are surveying a flooded archaeological site. Water ripples on the surface above it have a frequency of 2.5 Hz and a distance of 0.80 m between neighbouring crests. What is the speed of the ripples?

A technician uses an ultrasonic leak detector working at 40 kHz on a data-centre cooling pipe, but cannot hear it directly. What is the reason?

A cyclist's satellite navigation unit receives microwave signals from a satellite. Compared with visible light, how do microwaves behave in a vacuum?

An archaeologist stands in a large underground chamber and claps her hands once. Take the speed of sound in air as 340 m/s.

A data centre sends signals along an optical fibre using infrared radiation of wavelength 1500 nm (1 nm = 1 × 10⁻⁹ m). The speed of electromagnetic waves in a vacuum is 3.0 × 10⁸ m/s.

A gamer's wireless controller sends signals using infrared radiation. Which type of electromagnetic wave has a longer wavelength than infrared?

Waves on a reservoir have frequency 0.50 Hz and wavelength 3.0 m. What is the speed of the waves?

A maintenance worker taps one end of a long steel water pipe. A colleague at the other end can hear the sound travelling through the steel wall, the water in the pipe and the air outside the pipe. Through which does the sound arrive first?

Ultraviolet lamps are used in a pharmacy to sterilise equipment.

A gamer uses a plane mirror to check a webcam position.

A train's horn sends a sound wave through the air to a person standing beside the track. Which statement about the sound wave is correct?

An astronomer's telescope detects radio waves, infrared, ultraviolet and gamma rays from a distant nebula. Which row lists these in order of increasing frequency?

An athlete in a gym stands 2.0 m in front of a large plane mirror. What is the distance between the athlete and their image?

A spectrometer attached to an astronomer's telescope uses a glass prism to split starlight into a spectrum.

An astronomer wants to estimate the focal length of a converging lens.

Surface waves in a marine aquarium have a frequency of 4.0 Hz and a wavelength of 0.15 m. What is the speed of the waves?

A logistics depot uses radio tags to track pallets, a barcode scanner that emits red light, and an X-ray scanner to check sealed containers. Which statement about these three types of wave is correct?

A blue whale produces calls of frequency 15 Hz. Humans with normal hearing can detect sounds from 20 Hz to 20 kHz. Which of these frequencies is too low for a human to hear?

A logistics company uses three kinds of electromagnetic radiation: radio waves of frequency 900 MHz for tracking tags, red light for barcode scanners and X-rays to inspect cargo containers.

A retail store plays background music through a loudspeaker. Which statement about the sound waves from the loudspeaker is correct?

A wave-energy device floats at sea. Water waves of frequency 0.25 Hz and wavelength 40 m pass it. What is the speed of these waves?

A hospital sterilises surfaces using a lamp that emits radiation with a higher frequency than visible light and a lower frequency than X-rays. Which type of radiation is this?

A wave-energy buoy bobs up and down as water waves pass it. 15 wave crests pass the buoy in 60 s. The distance between neighbouring crests is 24 m.

A shop mirror is used to reflect light from a window to a counter. A ray of light strikes the plane mirror at an angle of incidence of 35°.

A volcano emits low-frequency sound waves of frequency 8.5 Hz. The speed of sound in the air is 340 m/s. What is the wavelength of these waves?

In a theatre, a technician uses lamps that give out ultraviolet radiation, visible light, infrared radiation and microwaves. Which list shows these in order of increasing wavelength?

Water waves of wavelength 12 m reach the entrance to a harbour. The entrance is a gap in the sea wall 10 m wide. Which change would make the diffraction at the gap smaller?

A volcano erupts with a loud explosion. An observer is 6.8 km from the volcano. The speed of sound in the air is 340 m/s.

A stage actor stands in front of a large plane mirror at the back of a theatre stage.

A mountaineer on a glacier shouts towards a rock face and hears the echo 2.4 s later. The speed of sound in the cold air is 340 m/s. How far away is the rock face?

A telecoms company uses microwaves for a satellite link and infrared radiation in an optical fibre. Which statement about these two types of electromagnetic wave is correct?

A mountain guide blows a whistle and then blows it again so that the note is louder but has the same pitch. Which row describes the change in the sound wave?

A mountaineer at the foot of a cliff shouts and hears an echo 3.6 s later. The speed of sound in the air is 340 m/s.

A food scientist uses a thin converging lens of focal length 6.0 cm to inspect a grain of salt.

A narrow beam of white light passes through a glass prism and a spectrum is produced on a screen. Later, a mountaineer wears goggles that block ultraviolet radiation from the Sun at high altitude.

Which list shows types of electromagnetic wave in order of increasing wavelength?

A guitarist plucks a string harder, without changing the length or tension of the string. How does the sound change?

Air traffic control radar emits pulses of microwaves of frequency 3.0 × 10⁹ Hz. Microwaves travel through air at 3.0 × 10⁸ m/s.

Water waves travel along an irrigation channel. A student counts 15 waves passing a fixed point in 6.0 s. The distance between neighbouring crests is 0.80 m.

During an excavation, a student models ground vibrations by sending waves along a rope. The waves have frequency 4.0 Hz and wavelength 0.75 m. What is the speed of the waves?

Archaeologists examine a sealed jar using X-rays. Which statement about all electromagnetic waves travelling in a vacuum is correct?

A thermal imaging camera in a data centre finds hot server racks. Which type of electromagnetic radiation does the camera detect?

Divers at an underwater archaeological site watch water waves pass a marker buoy on the surface. The distance between neighbouring crests is 4.5 m.

A technician in a data centre uses a range of electromagnetic waves. The speed of electromagnetic waves in a vacuum is 3.0 × 10⁸ m/s.

Engineers studying a bridge compare light waves and sound waves. Which row is correct?

Water waves pass under a bridge. The vertical distance from the top of a crest to the bottom of the next trough is 1.2 m. What is the amplitude of the waves?

Which frequency of sound can be heard by a healthy young person?

A space probe sends a radio signal to Earth. The signal takes 1500 s to arrive. The speed of radio waves in space is 3.0 × 10⁸ m/s.

A cable on a bridge vibrates at right angles to its length, and a wave travels along it. The wave has period 0.40 s and wavelength 3.0 m.

A wave machine in a swimming pool makes waves of wavelength 0.50 m and frequency 1.6 Hz. What is the speed of the waves?

Which list shows types of electromagnetic radiation in order of increasing wavelength, starting with the shortest?

A wave machine in a swimming pool produces water waves that travel along the pool.

A wind farm control room communicates with each turbine using radio waves.

A library has a large plane mirror fixed to one wall.

A beekeeper taps the wall of a hive and the sound travels through the air to her ear. Which statement about the air particles as the sound wave passes is correct?

Four types of electromagnetic radiation are radio waves, microwaves, infrared and X-rays. Which list shows them in order of increasing wavelength?

Water waves of wavelength 0.40 m in a hospital hydrotherapy pool pass through a gap between two barriers. Which width of gap produces the most noticeable diffraction of the waves?

A beekeeper holds a microphone close to a hive and records a steady buzzing sound of frequency 200 Hz. The speed of sound in air is 340 m/s.

A Formula 1 driver checks a flat rear-view mirror. Light from a following car reaches the mirror along a ray that makes an angle of 28° with the surface of the mirror.

Ripples spread across a swimming pool. The source vibrates at 2.5 Hz and the distance between neighbouring crests is 0.40 m. What is the speed of the ripples?

A librarian claps once in a large empty hall and hears an echo 0.40 s later. The speed of sound in air is 330 m/s. How far away is the wall that reflects the sound?

Radar at a wind farm uses microwaves. Which type of electromagnetic radiation has a higher frequency than microwaves but a lower frequency than visible light?

A wind farm uses radar with microwaves of frequency 9.4 GHz (9.4 × 10⁹ Hz). The speed of electromagnetic waves in air may be taken as the same as in a vacuum.

A floating ball in a swimming pool bobs up and down 15 times in 10 s as ripples pass it. The distance between neighbouring crests of the ripples is 0.40 m. The ripples travel horizontally across the pool.

On a water-supply reservoir, a student counts 12 wave crests passing a fixed buoy in 4.0 s. The distance between neighbouring crests is 0.50 m. What is the speed of the waves?

Gamma rays are used to sterilise surgical instruments before they are packed. Which statement about gamma rays is correct?

Water waves of frequency 0.80 Hz and wavelength 2.5 m travel across a reservoir that supplies a town. A sensor sits 30 m from the shore.

In an escape-room game, a ray from a laser pointer strikes a plane mirror. The angle between the ray and the surface of the mirror is 28°.

A water-treatment works uses ultraviolet lamps to disinfect drinking water.

Waves in a swimming pool have a frequency of 2.0 Hz and a wavelength of 0.25 m. What is the speed of the waves?

Four types of electromagnetic wave are listed. Which one has the shortest wavelength?

A technician at a wind farm uses a thermal imaging camera to find an overheating gearbox. Which type of radiation does the camera detect?

A swimmer makes waves in a pool. The distance between neighbouring crests is 0.40 m. A float on the water is passed by 10 complete waves in 8.0 s.

A mirror is fixed to the wall of a library corridor.

Archaeologists use ground-penetrating radar, which sends pulses of radio waves into the soil to find buried walls.
Which statement about radio waves is correct?

A data centre uses Wi-Fi signals of frequency 2.4 GHz. These are electromagnetic waves travelling at 3.0 × 10⁸ m/s in air.
What is the wavelength of the signals?

A thermal-imaging camera in a data centre detects electromagnetic radiation to find overheating servers.
Which list shows electromagnetic waves in order of increasing frequency?

In a ripple tank, a vibrating bar makes straight water waves. A student counts 5 complete waves passing a fixed mark in 2.0 s. The wavelength is 0.040 m.

A data centre uses Wi-Fi for staff devices and thermal cameras to monitor equipment. Electromagnetic waves are used in both.

Waves on the surface of a swimming pool have a wavelength of 0.40 m and a frequency of 1.5 Hz. What is the speed of the waves?

Which list shows electromagnetic waves in order of increasing wavelength?

Light passes from air into the glass of a library display case. Which quantity is the same in the air and in the glass?

A pest-control device in a library store room emits sound of one frequency. Which frequency is ultrasound for a human listener?

Waves travel across the surface of a swimming pool.

A train driver sounds a horn that emits a note of frequency 440 Hz. The speed of sound in air is 330 m/s. What is the wavelength of the sound?

A telescope detects radiation from a distant galaxy in several regions of the electromagnetic spectrum. Which list shows the radiation in order of increasing wavelength?

An underwater camera in a swimming pool records a swimmer. Light travels from the air into the water. What happens to the frequency and the wavelength of the light as it enters the water?

A stadium announcer speaks into a microphone and the sound is played through loudspeakers. A spectator sits some distance from a loudspeaker. The speed of sound in air is 340 m/s.

A railway company uses an infrared camera to check for overheating wheel bearings. The train driver also communicates by radio waves of frequency 125 MHz (1.25 × 10⁸ Hz). All electromagnetic waves travel at 3.0 × 10⁸ m/s in a vacuum.

A wave machine in a swimming pool makes 15 wave crests pass a floating ball in 10 s. The distance between neighbouring crests is 0.40 m. What is the speed of the waves?

Microwaves and ultraviolet radiation both travel through a vacuum. Which statement compares them correctly?

Which type of electromagnetic radiation is used in a television remote control?

A wave machine in a swimming pool makes 24 waves in 20 s. The distance between neighbouring crests is 0.35 m. A small float on the surface bobs up and down as each wave passes.