Physics Module 6

Question 1

What is the incident ray?

Answer 1

The incoming ray of light

Question 2

What is the reflected/refracted ray?

Answer 2

The outgoing ray of light

Question 3

What is the normal?

Answer 3

A line drawn at a right angle to the reflective/transparent surface

Question 4

What is the angle of incidence?

Answer 4

The angle between the incident ray and the normal

Question 5

What is the angle of reflection/refraction?

Answer 5

The angle between the reflected/refracted ray and the normal

Question 6

What are the two laws of reflection?

Answer 6

• The angle of incidence is equal to the angle of reflection
• The incident ray, the reflected ray and the normal all lie in the same plane

Question 7

How do images appear in a plane mirror?

Answer 7

Laterally inverted (flipped)

Question 8

What is a real image?

Answer 8

An image formed by rays of light focusing (converging) to a single point and being projected onto a surface

Question 9

What is a virtual image?

Answer 9

An image formed by extrapolated rays of light that are not formed physically by rays. It cannot be formed on a screen.

Question 10

What are the rules for the size and position of an image in a mirror?

Answer 10

• Image the same size as object
• Image same distance from mirror as object
• A line joining the object and image would pass through the mirror at a right angle

Question 11

What is refraction?

Answer 11

The bending of light as it travels at a different speed through a different medium

Question 12

If the transparent material has parallel sides, how does the light emerge?

Answer 12

Parallel to its original direction

Question 13

If the transparent material does not have parallel sides, how does the light emerge?

Answer 13

Deviated (different to its original direction)

Question 14

How do you define the refractive index of a material?

Answer 14

• speed of light in a vaccum / speed of light in the medium
  OR
• sin (angle of incidence) / sin (angle of refraction)

Question 15

What happens to white light when it refracts through a prism?

Answer 15

It disperses into a spectrum

Question 16

What is total internal reflection?

Answer 16

When light hits the inside of a transparent material at an angle greater than the critical angle, and is internally reflected entierly

Question 17

What happens if a light ray hits the inside of a transparent material at an angle lesser than the critical angle?

Answer 17

The ray splits into a refracted ray and a weaker reflected ray

Question 18

What happens if a light ray hits the inside of a transparent material at the critical angle?

Answer 18

The ray splits, but the refracted ray only just leaves the surface

Question 19

What happens if a light ray hits the inside of a transparent material at an angle greater than the critical angle?

Answer 19

There is no refracted ray - the inside of the transparent material acts like a perfect mirror

Question 20

What are the properties of a convex (converging) lens?

Answer 20

• Thicker in the middle, thinner at the edges
• Rays parallel to the principle axis are bent inwards when they pass through it
• Principle focus is where the rays converge

Question 21

What are the properties of a concave (diverging) lens?

Answer 21

• Thinner in the middle, thicker at the edges
• Rays parallel to the principle axis are bent outwards
• Principle focus is where the rays appear to diverge from if extrapolated

Question 22

What is the principle axis?

Answer 22

The ray of light that passes through the centre of a lens at a 90 degree angle

Question 23

What is focal length?

Answer 23

The distance between the centre of a lens and the principle focus

Question 24

What are the properties of a real image formed by a convex lens?

Answer 24

• Inverted (upside-down)
• Diminished (smaller than object) if object is far away
• Enlarged (larger than object) the closer the object gets

Question 25

How can a convex lens create a virtual image?

Answer 25

If an object is closer to the lens than its principle focus an upright, enlarged virtual image is created (magnifying glass)

Question 26

What kind of image can a concave lens create?

Answer 26

An upright, diminished, virtual image

Question 27

What are the names the categories of the electromagnetic spectrum, from lowest to highest frequency?

Answer 27

• Radio waves
• Micro waves
• Infrared waves
• Visible light
• Ultraviolet waves
• X-rays
• Gamma rays

Question 28

What are uses of radio waves?

Answer 28

• Long distance radio broadcasts
• TV broadcasts

Question 29

What are uses of micro waves?

Answer 29

• Mobile phones
• Wi-Fi
• Beaming TV, data and telephone signals to satellites
• Heating food

Question 30

What are uses of infrared waves?

Answer 30

• Motion sensors
• Infrared cameras
• Remote controllers for televisions
• Electric heaters

Question 31

What are uses of visible light?

Answer 31

• Lasers
• Optical fibres (cable TV, high-speed broadband, telephone networks)

Question 32

What are uses of ultraviolet waves?

Answer 32

• Sterilisation (killing bacteria/germs)
• Fluorescence (glow in the dark ink, bank notes)

Question 33

What are uses of X-rays?

Answer 33

• Take pictures of inside the body (medical & security checks)
• Reveal flaws inside metal

Question 34

What are uses of gamma waves?

Answer 34

• Sterilisation
• Killing cancer cells