Images, mirrors and lenses

Question 1

A real image is where

Answer 1

the light from the object comes together to form an image on a screen.

Question 2

A virtual image is when

Answer 2

the rays are diverging, so the light from the object appears to be coming from completely different place.

Question 3

When you look in the mirror, what sort of image do you see?

Answer 3

virtual, because the object appears to be behind the mirror

Question 4

To describe an image properly, you need to say 3 things, what?

Answer 4

1. How big it is compared to the object.
2. Whether its upright or inverted.
3. whether its real or virtual.

Question 5

What is the law of reflection?

Answer 5

angle of INCIDENCE= angle of REFLECTION

Question 6

Refraction of light

Answer 6

is when the waves of light change direction as they enter a different medium.

Question 7

What is refraction caused by?

Answer 7

The change in speed of the waves due to the change in density.

Question 8

3 points for a ray diagram of a plane mirror

Answer 8

1. The image is the same size as the object
2. It is as far behind the mirror as the object is in front.
3. formed from diverging rays so is virtual.

Question 9

Concave

Answer 9

curved mirror, shiny on the inside, light shining on it will diverge

Question 10

what is the centre of the mirrors surface called?

Answer 10

Vertex

Question 11

What is halfway between the vortex and the centre of curvature C?

Answer 11

Focal point, F

Question 12

How do you draw a ray diagram for an image in a concave mirror?

Answer 12

1. An incident ray parallel to the axis will pass through the focal point when its reflected.
2. An incident ray passing through the focal point will be parallel to the axis when its reflected.

Question 13

How do you draw a ray diagram for an image in a concave mirror?

Answer 13

1. An incident ray parallel to the axis will reflect so that the reflected ray seems to come from the focal point.
2. An icident ray that can be extended to pass through the focal point will be parallel to the axis when its reflected.

Question 14

The image in a convex mirror is always…

Answer 14

virtual, upright, smaller than the object and behind the mirror, closer than F.

Question 15

What does a ray bend toward as it enters a denser medium?

Answer 15

the normal

Question 16

Different wavelengths of light refract by

Answer 16

different amounts

Question 17

Why doesn’t a rectangular prism produce a rainbow effect like a triangular prism?

Answer 17

The boundaries are parallel so the rays bend back again by the same amount as they leave so they meet up again and white light emerges.

Question 18

What is a converging lens?

Answer 18

A lens which is convex

Question 19

what is a diverging lens?

Answer 19

A lens which is concave.

Question 20

What are the 3 rules for refraction in a converging lens?

Answer 20

1. An incident ray parallel to the axis refracts through the lens and passes through the focal point on the other side.
2. An incident ray passing throough the focal point refracts through the lens and travels parallel to the axis.
3. An incident ray through the centre carries on in the same direction.

Question 21

What are the 3 rules for refractio in a diverging lens?

Answer 21

1. An incident ray paralell to the axis, refracts and travels in line with the focal point( appearing to come from it)
2. An incident ray towards F refracts and travels parallel to the axis.
3. An incident ray passing through the centre carries on in the same direction.

Question 22

What sort of image does a diverging lens produce?

Answer 22

virtual, upright, smaller than object, same side of lens to object sort of image.

Question 23

What sort of lenses do magnifying glasses use?

Answer 23

Convex

Question 24

For a magnifying glass to magnify, the object mustbe..

Answer 24

Closer to the lens then the focal point.

Question 25

What sort of image does a magnifying glass produce?

Answer 25

Virtual image.

Question 26

What is the formula for magnification?

Answer 26

Magnification= image height/ object height

Question 27

What sort of image is an image on a film?

Answer 27

A real image.

Question 28

Why is the image on a film smaller?

Answer 28

the object is a lot further away from the focal length of the lens.