Lenses

Question 1

What’s a convex lens

Answer 1

Refract parallel rays of light inward to a single point (principle focus)
Also called a converging lens

Question 2

What is a concave lens

Answer 2

Refract parallel rays of light outwards (disperse the light)

Question 3

Where will the principle for us be found on a lens diagram

Answer 3

Will always sit on the axis (line passing through the middle)

Question 4

What is the focal length

Answer 4

Distance between principle focus and centre of the lens
(Shorter the focal length the more powerful the lens (refract more strongly))

Question 5

How would a lens be made more powerful

Answer 5

Make it more curved
Use a different material

Question 6

Where are images formed

Answer 6

At points where all the light rays from a particular point on an object appear to form together

Question 7

What is a real image

Answer 7

Light rays do actually come together to form the image

Question 8

What is a virtual image

Answer 8

Formed when the light rays don’t come together where the image appears to
(Uses virtual rays not light rays)

Question 9

Things to comment on when in an exam

Answer 9

If the image is upright or inverted
If the image is bigger or smaller than the object
If the image is real or virtual

Question 10

What type of image will a concave lens produce

Answer 10

Virtual

Question 11

What type of image will a convex lens produce

Answer 11

Real

Question 12

What happens if the object is between focal point and centre of lens

Answer 12

Rays will never meet