WavesOxford AQA IGCSE Physics: Topic test

20 questions, 54 marks

Oxford AQA IGCSE Physics

Waves topic test

Total 54 marks

Name

Class

Date

1
A physics technician sets a mechanical vibrator oscillating at the edge of a long measuring tank filled with water, producing straight waves that travel across the water's surface at a frequency of 5 Hz, each with a wavelength of 0.08 m.
(a)
Which type of wave are the water waves in this tank, in terms of the direction of oscillation relative to energy transfer?
[1 mark]
AEnergy is transferred but there is no oscillation at all
BLongitudinal, with oscillations parallel to the direction of energy transfer
CTransverse, with oscillations perpendicular to the direction of energy transfer
DA standing wave that transfers no energy
(b)
Which quantity describes the number of complete waves passing a fixed point each second?
[1 mark]
AWavelength
BAmplitude
CPeriod
DFrequency
(c)
Calculate the speed of the waves crossing the tank.
[2 marks]
Total for question 1: 4 marks
2
A security firm installs an infrared beam sensor across a warehouse doorway to detect intruders, and separately uses ultraviolet-sensitive ink to mark valuable equipment with a hidden security code, visible only under a UV lamp.
(a)
Which property is shared by all types of electromagnetic wave, including the infrared beam and the ultraviolet light?
[1 mark]
AThey all travel at the same speed through a vacuum
BThey all have the same wavelength
CThey all have the same frequency
DThey can only travel through air
(b)
Why is ultraviolet-sensitive security marking useful for identifying stolen equipment?
[1 mark]
AUV radiation can pass through solid metal so the mark can be read from inside a locked cabinet
BThe ink absorbs UV light and re-emits visible light, making the mark visible only under a UV lamp
CUV radiation destroys the equipment's surface, revealing a permanent mark
DUV light has a lower frequency than visible light, making the mark brighter
(c)
Explain one hazard associated with ultraviolet radiation exposure to human skin, and state one precaution that could be taken to reduce this hazard when handling the UV lamp.
[2 marks]
Total for question 2: 4 marks
3
A factory installs an ultrasonic level sensor above a large storage tank of liquid. The sensor sends a pulse of ultrasound straight down towards the liquid's surface and detects the reflected pulse 0.024 s after it was sent. The speed of sound in the air above the liquid is 340 m/s.
(a)
State what is meant by 'ultrasound', and calculate the distance from the sensor to the surface of the liquid.
[3 marks]
(b)
Explain, in terms of the properties of ultrasound at a boundary between two different media, why only part of the ultrasound pulse is reflected back to the sensor, and suggest one advantage of using this ultrasonic method to measure the liquid level rather than dipping a probe into the tank.
[4 marks]
Total for question 3: 7 marks
4
A telecommunications engineer compares two ways of sending a signal across a factory site: bouncing a laser beam off a series of flat mirrors mounted on poles, or sending light along a buried optical fibre cable that relies on total internal reflection to keep the light inside the fibre as it repeatedly hits the fibre's inner wall.
(a)
State the law of reflection, and describe how a light ray would reflect from one of the flat mirrors mounted on a pole if it strikes the mirror's surface at an angle of 35 degrees to the normal.
[6 marks]
(b)
The optical fibre has a critical angle of 42 degrees for light travelling inside it. Explain why light travelling inside the fibre and hitting the fibre wall at an angle of 50 degrees to the normal undergoes total internal reflection, and explain one practical advantage of using the optical fibre over the mirror relay system for sending the signal across the site.
[6 marks]
Total for question 4: 12 marks
5
A driver checks the interior rear-view mirror of her car, a small flat mirror angled to show the road behind, before reversing out of a parking space.
(a)
Which statement correctly describes the image of a car seen in this flat interior mirror?
[1 mark]
AReal, inverted and magnified
BReal, upright and the same size
CVirtual, upright and laterally inverted
DVirtual, inverted and laterally inverted
(b)
If the mirror is tilted so that a ray of light from a following car's headlight strikes it at 20 degrees to the normal, at what angle to the normal does the reflected ray travel towards the driver's eye?
[1 mark]
A10 degrees
B40 degrees
C70 degrees
D20 degrees
(c)
State two properties, other than being laterally inverted, of the image formed in this flat mirror.
[2 marks]
Total for question 5: 4 marks
6
An optician explains to a new patient how the ciliary muscles and suspensory ligaments inside the eye change the shape of the lens to focus on objects at different distances, first looking at a distant road sign, then reading a menu held close to the face.
(a)
When the patient looks from the distant road sign to the nearby menu, what happens to the eye's lens?
[1 mark]
AThe ciliary muscles contract, the suspensory ligaments slacken, and the lens becomes more curved (rounder)
BThe ciliary muscles relax, the suspensory ligaments tighten, and the lens becomes flatter
CThe lens moves further away from the retina
DThe pupil changes shape to focus the image
(b)
The optician tells the patient that her 'near point' is approximately 25 cm. What does this mean?
[1 mark]
AThe furthest distance at which the eye can focus clearly, typically infinity
BThe closest distance at which the eye can focus clearly
CThe distance between the lens and the retina
DThe distance at which the pupil is fully dilated
(c)
State the function of the retina in the eye, and state where the far point of a normal eye is located.
[2 marks]
Total for question 6: 4 marks
7
A radio engineer investigates how a weak signal from a local FM radio station diffracts around the corner of a large office building, allowing a listener on the far side of the building to still receive a faint signal, while a stronger long-wave signal from a distant transmitter diffracts more noticeably around the same building.
(a)
Explain what is meant by diffraction of a wave, and state the condition under which diffraction is most noticeable.
[3 marks]
(b)
Explain why the long-wave radio signal diffracts more noticeably around the building than the FM radio signal, and describe what happens to the part of the FM wave's energy that strikes the building directly rather than diffracting around it.
[4 marks]
Total for question 7: 7 marks
8
A hospital is deciding whether to use an X-ray scan or an ultrasound scan to investigate a patient's suspected soft-tissue injury to a tendon, without exposing the patient to unnecessary radiation dose.
(a)
Explain how an X-ray image is formed as X-rays pass through the body, and explain why exposure to X-rays must be carefully monitored and minimised.
[6 marks]
(b)
Explain how an ultrasound scan can be used instead to investigate the tendon injury, and explain why doctors might prefer ultrasound over an X-ray scan for this soft-tissue injury.
[6 marks]
Total for question 8: 12 marks

End of questions