7th grade light, sound and waves

Question 1

You see lightning and hear the thunder 2 seconds later. Sound travels at about 340 m/s. About how far away is the storm, in metres?

Answer m

Question 2

What does a prism do to white light?

• A. stops it completely
• B. splits it into a spectrum of colours
• C. turns it black
• D. makes it brighter

Question 3

How sound travels: which statement is NOT true?

• A. Sound waves are longitudinal.
• B. Sound travels faster than light.
• C. Whales can communicate over long distances underwater.
• D. Sound travels faster in water than in air.

Question 4

How do bats find insects in the dark?

• A. They send out high-pitched sounds and listen for echoes
• B. They use magnets
• C. They smell them from far away
• D. They glow

Question 5

Colour and light: which statement is NOT true?

• A. Black objects absorb most of the light that falls on them.
• B. Light slows down when it enters glass or water.
• C. A red filter lets red light through and absorbs other colours.
• D. White objects absorb all colours.

Question 6

In which direction do air particles vibrate when a sound wave passes?

• A. up and down, at right angles to the wave
• B. backwards and forwards, parallel to the direction the sound travels
• C. they do not move
• D. in circles

Question 7

You shout towards a cliff and hear the echo 1.5 s later. Sound travels at 340 m/s. How far away is the cliff, in metres?

Answer m

Question 8

Sound travels at about 1500 m/s in water. How far does it travel in 5 s, in m?

Answer m

Question 9

You see lightning and hear the thunder 4 seconds later. Sound travels at about 340 m/s. About how far away is the storm, in metres?

Answer m

Question 10

What colour does a green leaf look under only red light?

• A. black (very dark)
• B. green
• C. red
• D. white

Question 11

How sound travels: which statement is NOT true?

• A. Whales can communicate over long distances underwater.
• B. Sound waves are longitudinal.
• C. Sound travels fastest in gases.
• D. Sound travels faster in water than in air.

Question 12

How do bats find insects in the dark?

• A. They glow
• B. They use magnets
• C. They send out high-pitched sounds and listen for echoes
• D. They smell them from far away

Question 13

Colour and light: which statement is NOT true?

• A. White light is a mixture of colours.
• B. Black objects absorb most of the light that falls on them.
• C. Light slows down when it enters glass or water.
• D. Light travels at the same speed in glass as in air.

Question 14

An alarm clock rings inside a jar. As the air is pumped out, the ringing gets quieter. Why?

• A. Air makes sound quieter
• B. Sound needs particles to travel through, and there are fewer left
• C. The clock stops ringing
• D. Glass absorbs all sound