Waves Banker

1. (a) A water wave has a frequency of 4.0 Hz and a wavelength of 0.25 m. What is the speed of the wave?A 0.063 m/sB 1.0 m/sC 4.3 m/sD 16 m/s [1]

A student watches straight waves in a ripple tank. 15 waves pass a fixed point in 5.0 s. The distance between neighbouring crests is 2.4 cm.

1. (a) Calculate the frequency of the waves. [1]
2. (b) Calculate the speed of the waves. [2]
3. (c) Water waves are transverse. State the difference between a transverse wave and a longitudinal wave, and give one example of a longitudinal wave. [3]

Waves in a ripple tank have a frequency of 12 Hz. In the deep region their speed is 18 cm/s. They pass into a shallow region where their speed is 12 cm/s.

1. (a) Calculate the wavelength in the deep region. [2]
2. (b) State the frequency in the shallow region and calculate the wavelength there. [2]
3. (c) The waves meet the boundary at an angle. Describe what happens to their direction of travel as they enter the shallow region. [1]

1. (a) An earthquake produces P-waves and S-waves. Which row correctly describes both types of seismic wave?A P-waves longitudinal; S-waves transverseB P-waves transverse; S-waves longitudinalC P-waves longitudinal; S-waves longitudinalD P-waves transverse; S-waves transverse [1]

A student shakes one end of a long rope up and down to send a transverse wave along it. In a photograph, the first crest is 0.30 m from her hand and the fourth crest is 2.10 m from her hand. The vertical distance from a crest to a trough is 16 cm. She moves her hand up and down 2.5 times per second.

1. (a) Calculate the wavelength of the wave. [2]
2. (b) State the amplitude of the wave. [1]
3. (c) Calculate the speed of the wave and its period. [3]

A long-wave radio transmitter broadcasts at a frequency of 198 kHz. Radio waves travel at 3.0 × 10⁸ m/s.

1. (a) Calculate the wavelength of the radio waves. [2]
2. (b) Describe how the amount of diffraction of a wave passing through a gap depends on the width of the gap compared with the wavelength. [2]
3. (c) Use your answers to explain why long-wave radio can be received in a valley between mountains in Gilgit-Baltistan, while short-wavelength signals from the same direction cannot. [2]

A student investigates how the speed of water waves in a long tray depends on the depth of water. She lifts one end of the tray slightly and lets it drop, then times how long the wave takes to travel to the far end and back, a total distance of 1.80 m. Each time is an average of three readings.depth d / cm: 1.0, 2.0, 3.0, 4.0, 5.0time t / s: 5.75, 4.07, 3.32, 2.87, 2.57

1. (a) Calculate the wave speed v for the depths 1.0 cm and 3.0 cm. Give your answers to 2 significant figures. [2]
2. (b) A student suggests that the speed is directly proportional to the depth. State whether the results support this, using values from the results. [2]
3. (c) Suggest one difficulty in timing the wave accurately and one way of overcoming it. [2]
4. (d) State one variable that should be kept constant. [1]

A ray of light strikes a flat plane mirror. The angle of incidence is 35°.

1. (a) State the angle of reflection. [1]
2. (b) Calculate the angle between the reflected ray and the surface of the mirror. [1]
3. (c) Ayesha stands 1.5 m in front of a tall plane mirror. State the distance between Ayesha and her image. [1]
4. (d) Describe three properties of the image formed by a plane mirror. [3]

1. (a) A ray of light passes at an angle from air into water. Which row describes what happens to the light?A it speeds up and bends away from the normalB it slows down and bends towards the normalC it slows down and bends away from the normalD its speed is unchanged and it does not bend [1]

A ray of light travels from air into a glass block of refractive index 1.52. The angle of incidence at the air–glass surface is 50°. The speed of light in air is 3.0 × 10⁸ m/s.

1. (a) Calculate the angle of refraction in the glass. [3]
2. (b) Calculate the speed of light in the glass. [2]
3. (c) State what happens to the frequency of the light as it enters the glass. [1]

1. (a) The critical angle for light in a type of glass is 41.8°. What is the refractive index of the glass?A 0.67B 1.33C 1.50D 2.24 [1]

A student traces rays through a rectangular glass block on paper using optics pins. She measures the angle of incidence i at the first surface and the angle of refraction r inside the block.i / °: 20, 30, 40, 50, 60r / °: 13.0, 19.5, 25.5, 30.5, 35.5

1. (a) Calculate the refractive index n of the glass using the result for i = 50°. Give your answer to 3 significant figures. [2]
2. (b) The student plots a graph of sin i (y-axis) against sin r (x-axis). Describe the graph expected and state what its gradient represents. [2]
3. (c) Suggest two precautions to make the ray traces as accurate as possible. [2]

The speed of light in diamond is 1.24 × 10⁸ m/s. The speed of light in air is 3.0 × 10⁸ m/s.

1. (a) Calculate the refractive index of diamond. [2]
2. (b) Calculate the critical angle for diamond. [2]
3. (c) Use your answer to (b) to explain why a cut diamond sparkles brightly. [2]

An optical fibre used for broadband internet has a glass core of refractive index 1.48. Light travels along the core by repeated total internal reflection.

1. (a) Calculate the critical angle for the core–air boundary. [2]
2. (b) A ray inside the core strikes the boundary at an angle of incidence of 60°. State and explain what happens to the ray. [2]
3. (c) Another ray inside the core strikes the boundary at an angle of incidence of 38°. Calculate the angle of refraction of the ray that emerges into the air. [2]
4. (d) State one use of optical fibres in medicine. [1]

A ray of light strikes a plane mirror. The angle between the incident ray and the surface of the mirror is 40°.

1. (a) State the angle of reflection. [1]
2. (b) Calculate the angle between the incident ray and the reflected ray. [1]
3. (c) The mirror is rotated by 10° so that the angle of incidence increases. The incident ray does not move. Calculate the angle through which the reflected ray turns. [2]
4. (d) Explain why the image in a plane mirror is described as virtual. [1]

A thin converging lens is used in a simple camera.

1. (a) Explain what is meant by the principal focus of a converging lens. [2]
2. (b) Define the focal length. [1]
3. (c) A distant tree is photographed. The object is more than twice the focal length from the lens. Describe the image formed. [3]

1. (a) A narrow beam of white light passes through a glass prism and splits into a spectrum. Which colour is refracted (deviated) the most?A redB yellowC greenD violet [1]

An object 3.0 cm tall stands upright on the principal axis, 15 cm from a converging lens of focal length 10 cm.

1. (a) By drawing a scale ray diagram (or otherwise), determine the distance of the image from the lens. [3]
2. (b) Determine the height of the image. [1]
3. (c) State two other properties of the image. [2]

1. (a) A student holds a converging lens close to a page so that the print is closer to the lens than its principal focus. Which describes the image?A real, inverted, enlargedB virtual, upright, enlargedC virtual, inverted, diminishedD real, upright, same size [1]

When white light passes through a triangular glass prism, a band of colours can be seen on a screen.

1. (a) Name this effect. [1]
2. (b) State the seven colours of the visible spectrum in order of increasing frequency. [2]
3. (c) Explain why white light separates into colours in the prism. [2]
4. (d) Explain what is meant by monochromatic light. [1]

Rashid's grandfather can see distant mountains clearly but cannot read the newspaper held at a normal reading distance. His granddaughter can read easily but cannot see the scoreboard at the far end of a cricket ground clearly.

1. (a) Name the sight defect of the grandfather and state where light from the newspaper is focused in his eye without glasses. [2]
2. (b) Name the type of lens that corrects his defect and explain how it works. [2]
3. (c) Name the granddaughter's defect, state the type of correcting lens and explain its effect. [3]

1. (a) List the regions of the electromagnetic spectrum in order of increasing frequency, starting with radio waves. [2]
2. (b) State the speed of all electromagnetic waves in a vacuum. [1]
3. (c) Give one use each of microwaves and X-rays. [2]
4. (d) State one harmful effect on people of excessive exposure to ultraviolet radiation. [1]

Electromagnetic waves travel at 3.0 × 10⁸ m/s.

1. (a) A Wi-Fi router uses a frequency of 2.4 GHz. Calculate the wavelength. [2]
2. (b) An FM radio station broadcasts at 101 MHz. Calculate the wavelength. [1]
3. (c) A geostationary satellite is 3.6 × 10⁷ m above a ground station. Calculate the time for a microwave signal to travel from the station to the satellite. [2]
4. (d) Name the region of the electromagnetic spectrum used for communicating with satellites. [1]

1. (a) Describe the harmful effect on people of excessive exposure to each of: (i) microwaves, (ii) infrared, (iii) X-rays and gamma rays. [3]
2. (b) A radiographer in a hospital takes many X-ray images each day. Suggest two precautions she takes to reduce her own exposure. [2]
3. (c) State two uses of infrared radiation. [2]

Telephone calls between Karachi and Lahore are carried as digital signals along optical fibres.

1. (a) Describe the difference between an analogue signal and a digital signal. [2]
2. (b) Explain two advantages of transmitting the call as a digital signal rather than an analogue one. [4]
3. (c) Name the region of the electromagnetic spectrum usually used in optical fibres. [1]

1. (a) Which of these electromagnetic waves has the longest wavelength?A infraredB ultravioletC X-raysD microwaves [1]

A student stands 85 m from the tall wall of a school building and claps once. She hears the echo 0.50 s after the clap.

1. (a) Calculate the speed of sound in air from these results. [2]
2. (b) State the approximate range of frequencies that can be heard by a healthy human ear. [1]
3. (c) Explain why sound cannot travel through a vacuum. [1]

Ultrasound is used to produce images of an unborn baby in a hospital in Faisalabad, and in sonar on a survey ship in the Arabian Sea.

1. (a) State what is meant by ultrasound. [1]
2. (b) A pulse of ultrasound travels at 1500 m/s through body tissue. The echo from a boundary inside the body returns 6.5 × 10⁻⁵ s after the pulse is sent. Calculate the depth of the boundary below the probe, in cm. [2]
3. (c) The ship's sonar receives an echo from the sea bed 2.4 s after sending a pulse. The speed of sound in sea water is 1500 m/s. Calculate the depth of the sea. [2]

Two students measure the speed of sound on a sports field. Student A stands 150 m from student B and bangs two cymbals together. Student B starts a stopwatch when he sees the cymbals meet and stops it when he hears the sound. Times recorded: 0.48 s, 0.42 s, 0.45 s, 0.47 s.

1. (a) Calculate the average time. [1]
2. (b) Calculate the speed of sound. Give your answer to 2 significant figures. [2]
3. (c) Explain why the time taken for the light to reach student B can be ignored. [1]
4. (d) Suggest two improvements to the experiment. [2]

A microphone connected to an oscilloscope picks up a steady note from a flute. The trace shows exactly 4 complete waves across 10 horizontal divisions. The time-base is set at 0.50 ms per division. The speed of sound in air is 330 m/s.

1. (a) Calculate the period and the frequency of the note. [3]
2. (b) Calculate the wavelength of the note in air. [1]
3. (c) The flute then plays a louder note of higher pitch. Describe two changes to the trace, with the oscilloscope settings unchanged. [2]
4. (d) Sound travels through air, steel and water. State the medium in which sound travels fastest and the medium in which it travels slowest. [1]