P12

Question 1

What type of lens is thicker in the middle than at the edges?

Answer 1

Convex lenses

Question 2

Which type of lens causes light rays to diverge?

Answer 2

Concave

Question 3

Which type of lens is used in a camera?

Answer 3

convex

Question 4

What is a real image?

Answer 4

A real image is an image that can be projected onto a screen

Question 5

What is a virtual image?

Answer 5

An image from which rays of light appear to come but do not do so in reality

Question 6

What types of images do concave lenses form?

Answer 6

Only virtual images

Question 7

What name is given to a material that absorbs some wavelengths of visible light and transmits others?

Answer 7

A filter

Question 8

Why can we see through glass?

Answer 8

Almost all light waves are transmitted through glass, making it a transparent object

Question 9

What name is given to the distance between the lens and the principal focus?

Answer 9

Focal length

Question 10

What is an area of low pressure in a wave called?

Answer 10

A rarefraction

Question 11

What is denser (air, glass or water)?

Answer 11

Glass

Question 12

What happens to a light ray when it travels from water into air?

Answer 12

It bends away from the normal because it passes into a less dense material and speeds up

Question 13

What are the units for magnification?

Answer 13

Magnification has no units since it is a ratio of 2 quantities with the same units.

Question 14

What state of matter does sound travel the fastest?

Answer 14

Solids, because the particles are more tightly packed

Question 15

Waves transfer ____

Answer 15

energy from place to place, without transferring any matter

Question 16

What is the amplitude?

Answer 16

The amplitude of a wave is the distance from the centre line (or the still position) to the top of a crest. or to the bottom of a trough.

Question 17

What is frequency?

Answer 17

Frequency is the number of complete waves passing a certain point per second measured in Hz. 1 Hz is equal to 1 wave per second.

Question 18

What is wavelength?

Answer 18

The wavelength of a wave is the distance between a point on one wave and the same point on the next wave.

Question 19

What are transverse waves?

Answer 19

Transverse waves are waves whose oscillations are at right angles to the direction of travel and energy transfer.

Question 20

What are longitudinal waves?

Answer 20

In longitudinal waves, the oscillations are along the same direction as the direction of travel and energy transfer. (parallel)

Question 21

Examples of transverse waves

Answer 21

All EM waves and ripples on water

Question 22

Examples of longitudinal waves

Answer 22

Sound waves, seismic waves, P- waves

Question 23

What is the frequency range of human hearing?

Answer 23

20Hz - 20KHz

Question 24

What is reflection?

Answer 24

Reflection involves a change in direction of waves when they bounce off a barrier.

Question 25

What is refraction?

Answer 25

Refraction is the process by which a wave changes speed and sometimes direction upon entering a denser or less dense medium.

Question 26

What is the angle of incidence?

Answer 26

The angle of incidence is the angle between the incoming wave and the normal.

Question 27

What is the angle of reflection?

Answer 27

The angle of reflection is the angle between the reflected wave and the normal.

Question 28

Angle of Incidence is greater/equal/less than the Angle of Reflection

Answer 28

Angle of Incidence = Angle of Reflection

Question 29

What is the law of reflection?

Answer 29

The law of reflection states that, on reflection from a smooth surface, the angle of the reflected ray is equal to the angle of the incident ray.

Question 30

What is specular reflection?

Answer 30

Specular reflection happens when a wave is reflected in a single direction by a smooth surface E.g when light is reflected by a mirror you get a nice clear reflection

Question 31

What is diffuse reflection?

Answer 31

Reflection from a rough surface is called diffuse reflection because the reflected rays are scattered in lots of different directions

Question 32

high to low Electromagnetic Spectrum?

Answer 32

radio - microwave - infared - visible light - ultraviolet - x-rays - gamma rays

Question 33

what is radio waves used?

Answer 33

used to broadcast radio and television

Question 34

what is microwaves used for?

Answer 34

cooking,radar,telephone and other signals

Question 35

what is infared used for?

Answer 35

transmits heat from sun, fires radiators

Question 36

what is visible light used for?

Answer 36

makes things to be seen

Question 37

what is uv used for?

Answer 37

absorbed by skin

Question 38

what is rays used for?

Answer 38

used to view inside bodies and objects

Question 39

what is gamma rays used for?

Answer 39

used in medicine for killing cancer cells

Question 40

3 things all electromagnetic waves have in common

Answer 40

- transfers radiation as energy from waves - can travel through a vacum - travel at same speed

Question 41

What is the speed of light in a vacuum or air?

Answer 41

300,000,000 m/s

Question 42

Which colour is the best absorber of radiation?

Answer 42

Black

Question 43

What gases in the atmosphere change the balance of infrared radiation absorbed and emitted by the Earth?

Answer 43

Greenhouse gases change the balance of infrared radiation absorbed and emitted by the Earth.

Question 44

What health effects can ultraviolet waves cause?

Answer 44

Cause the skin to age prematurely and increase risk of developing skin cancer

Question 45

Uses of radio waves

Answer 45

Radio waves are used for communication such as broadcasting television and radio, communications and satellite transmissions.

Question 46

What is echo?

Answer 46

A reflection of sound waves from a smooth surface

Question 47

Uses of infrared

Answer 47

- security systems - thermal imaging - electrical heaters

Question 48

Define ultrasound

Answer 48

Ultrasound is sound with a frequency greater than 20,000 Hz