P14 - Light

Question 1

How does a lens form an image?

Answer 1

By refracting light

Question 2

How does a convex lens work?

Answer 2

Parallel rays of light are brought into focus at the principal focus

Question 3

What is the difference between focal points in convex and concave lenses?

Answer 3

Convex - The principal focus is where all the rays converge
Concave - The focal point is not a ‘real’ point in the concave lens, the image produced by a concave lens is always virtual

Question 4

What is the focal length?

Answer 4

The distance from the lens to the principal focus

Question 5

What is the image produced by a convex lens?

Answer 5

Real or virtual

Question 6

What is the image produced by a concave lens?

Answer 6

Virtual

Question 7

Which lens has a real focal point?

Answer 7

Convex

Question 8

How does a concave and convex lens form an image?

Answer 8

Using refracted light rays

Question 9

Why does magnification have no units?

Answer 9

It is a ratio

Question 10

What units can image height and object heigh be measured in?

Answer 10

Cm or mm

Question 11

What is the equation for the magnification of a lens?

Answer 11

Magnification = image height/object height

Question 12

What is a convex lens represented by in ray diagrams?

Answer 12

Double arrows

Question 13

What is a concave lens represented by in ray diagrams?

Answer 13

Opposite arrows

Question 14

What is visible light split into?

Answer 14

7 colours

Question 15

What does each colour have?

Answer 15

A wavelength and frequency

Question 16

Which one has the shortest wavelength and highest frequency?

Answer 16

Violet light

Question 17

Which one has the longest wavelength and lowest frequency?

Answer 17

Red light

Question 18

What is specular reflection?

Answer 18

Reflection from a smooth surface in a single direction

Question 19

What is diffuse reflection?

Answer 19

Reflection from a rough surface causes scattering

Question 20

How do colour filters work?

Answer 20

Absorb certain wavelengths(and colour) and transmit other wavelengths

Question 21

What is the colour of an opaque object determined by?

Answer 21

Which wavelength of light are more strongly reflected

Question 22

When does an object appear black?

Answer 22

When all wavelengths are absorbed

Question 23

When does an object appear white?

Answer 23

When all wavelengths are reflected equally

Question 24

What do transparent or translucent objects do with light?

Answer 24

Transmit light

Question 25

Describe and explain the appearance of a red object if it is in a room with only green light

Answer 25

- A red object normally appears red because it reflects the red part of the spectrum and absorbs all the other colours - if the object is in a green light it will absorb all of the green light and will not reflect any light - this means that the red object will appear black under a green light

Question 26

What do all objects do?

Answer 26

Emit radiation

Question 27

What the intensity and wavelength distribution depend on?

Answer 27

The temperature of the body

Question 28

What is a body at a constant temperature doing?

Answer 28

Absorbing radiation at the same rate as it is emitting radiation

Question 29

When does the temperature of a body increase?

Answer 29

When a body absorbs more radiation than it emits

Question 30

When does the temperature of a body decrease?

Answer 30

When a body emits more radiation than it absorbs

Question 31

What does the temperature of the Earth depend on?

Answer 31

- Rates of absorption and emission of radiation - reflection of radiation into space

Question 32

What is a body’s temperature determined by?

Answer 32

The balance between the incoming radiation it absorbs and the outgoing radiation it emits