4. Waves (AQA)

What is the term for the distance from the middle to the top of a wave?

• Wavelength

• Frequency

• Amplitude

• Trough

Answer explanation

The term for the distance from the middle to the top of a wave is called amplitude. It measures the height of the wave from its rest position to its peak, distinguishing it from wavelength and frequency.

Which type of wave does not need a medium to travel through?

• Longitudinal waves

• Sound waves

• Transverse waves

• Ultrasound waves

Answer explanation

Transverse waves, such as light waves, do not require a medium to travel through, unlike longitudinal waves and sound waves, which need a medium like air or water. Therefore, the correct answer is transverse waves.

What is the unit of measurement for frequency?

• Decibels

• Hertz

• Meters

• Amperes

Answer explanation

The unit of measurement for frequency is Hertz (Hz), which quantifies the number of cycles per second of a periodic phenomenon. Decibels measure sound intensity, meters measure distance, and amperes measure electric current.

What does the law of reflection state?

• Angle of incidence is greater than angle of reflection

• Angle of incidence is less than angle of reflection

• Angle of incidence is equal to angle of reflection

• Angle of incidence is unrelated to angle of reflection

Answer explanation

The law of reflection states that the angle of incidence, which is the angle between the incoming ray and the normal, is equal to the angle of reflection, the angle between the reflected ray and the normal.

What happens when light enters a more dense material?

• It speeds up

• It bends away from the normal

• It bends towards the normal

• It reflects back

Answer explanation

When light enters a denser material, it slows down and bends towards the normal due to the change in speed. This bending occurs because light travels more slowly in denser media compared to less dense ones.

What is the function of the pinna in the ear?

• To vibrate the eardrum

• To direct sound along the auditory canal

• To amplify sound

• To detect sound

Answer explanation

The pinna, or outer ear, functions primarily to direct sound waves into the auditory canal, helping to channel sound towards the eardrum for further processing.

What is the purpose of photoreceptors in the eye?

• To focus light

• To detect light and send signals to the brain

• To reflect light

• To absorb light

Answer explanation

Photoreceptors in the eye are specialized cells that detect light and convert it into electrical signals. These signals are then sent to the brain, allowing us to perceive images, making 'to detect light and send signals to the brain' the correct choice.

What is the term for sound waves above 20,000 Hz?

• Infrasound

• Ultrasound

• Supersound

• Megasound

Answer explanation

Sound waves above 20,000 Hz are referred to as ultrasound. In contrast, infrasound refers to sound below 20 Hz. Supersound and megasound are not standard terms used in acoustics.

What is the role of the lens in the eye?

• To create sound

• To reflect light

• To refract light and focus it on the retina

• To absorb light

Answer explanation

The lens in the eye refracts light, bending it to focus on the retina, which is essential for clear vision. This function distinguishes it from other options like creating sound or absorbing light.

What is the term for the bottom of a wave?

• Peak

• Crest

• Trough

• Amplitude

Answer explanation

The term for the bottom of a wave is 'trough'. The peak or crest refers to the top of the wave, while amplitude measures the height from the trough to the crest.