lenses

Question 1

converging lens

Answer 1

convex lens in which light rays that enter it parallel to its axis converge at a single point on opposite side

Question 2

diverging lens

Answer 2

concave lens in which light rays enter it paralle to its axis bend away or diverge from its axis

Question 3

principal axis

Answer 3

straight line passing through geometrical centre of lens
path of light ray along this axis is perpendicular to the surface and as such will be unchanged

Question 4

principal focus

Answer 4

point on the axis of lens to which parallel rays of light converge or from which they appear to diverge after refraction

Question 5

focal lenght

Answer 5

distance between centre of convex lens or concave mirror and focal point of lens
point where parallel rays of light meet or converge

Question 6

focal plane

Answer 6

the plane that is perpendicular to axis of a lens or mirror and passes through focal pointm

Question 7

magnification

Answer 7

process of enlarging apparent size of something
when less than one referred to as reduction or demagnification

Question 8

between f and 2f
id- beyond 2f

Answer 8

real inverted larger

Question 9

at 2 f
id at 2f

Answer 9

real inverted same size

Question 10

beyond 2f
id between f and 2f

Answer 10

real inverted smaller

Question 11

at f
no image

Question 12

between f and c
behind o

Answer 12

virtual erect larger