Light and Sound

Question 1

Define a luminous and non-luminous object and give examples of both. (4)

Answer 1

A luminous object gives off light, such as a light bulb. A non-luminous object doesn’t give off light, such as a table.

Question 2

Name the colours white light can be dispersed into. (7)

Answer 2

Red, orange, yellow, green, blue, indigo and violet.

Question 3

Describe how we see colours. (2)

Answer 3

We have sensors in our eyes that can sense red, green and blue light. Using combinations of these three colours, we can see many different colours.

Question 4

Describe how colours can be absorbed or reflected. (2)

Answer 4

Colours can be absorbed and reflected by all objects. A green leaf, for example, absorbs all colours apart from green and reflects the colour green.

Question 5

Describe how sound travels using a medium using the particle theory. (2)

Answer 5

When sound travels through a material/medium, the wave enters a particle, then the particle vibrates and ‘bumps’ another particle, and passes the energy from the sound wave through. This continues as the energy is transferred from particle to particle.

Question 6

Which medium does sound travel fastest through and why? (2)

Answer 6

Sound traves fastest through solids, because the particles are closer together.

Question 7

Which is faster: sound or light? (1)

Answer 7

Light is faster.

Question 8

Define amplitude, frequency and pitch. (3)

Answer 8

Amplitude is how loud a sound is, with a larger wave; frequency is how close together the waves are; and pitch is how high or low a sound is, determined by its frequency.

Question 9

How we hear sounds and how loud noises can damage hearing. (4)

Answer 9

We hear sound by the sound waves hitting our eardrum, it vibrating, and the vibrations being passed on to our cochlea, our auditory nerve and then to our brain. Loud noises can damage the hairs in the cochlea that pick up the vibrations, and can even burst the eardrum.