Geometric Optics

Question 1

Light

Answer 1

Is a form of energy that travels away from the source producing it at 3*10⁸ ms–¹

Question 2

Reflection

Answer 2

Is the bouncing of light off a larger object

Question 3

Laws of reflection

Answer 3

1: The incident ray,the Normal and the reflected ray all lie in the same plane at the point of incidence

2: The angle of incidence is equal to the angle of reflection

Question 4

Virtual Image

Answer 4

Is an image formed by the apparent intersection of light rays.

Such an image cannot be projected onto a screen and is always upright when viewed in the mirror

Question 5

Lateral inversion

Answer 5

The effect produced by a mirror in reversing images from left to right

Question 6

Parallax

Answer 6

The apparent movement of one object relative to another due to the motion of the observer

Question 7

Real Image

Answer 7

Is an image formed by the actual intersection of light rays

Question 8

Refraction

Answer 8

Is the bending of light when it travels from one medium to another.
It bends away from the normal when passing from a medium with a higher to a lower refractive index

Question 9

Laws of Refraction

Answer 9

1: The incident ray,the normal and the refracted ray all lie in the same plane at the point of incidence

2: The ratio of the sine of the angle of incidence to the sine of the angle of Refraction is a constant i.e Snell’s Law

n1sin(∅1)=n2sin (∅2)

Question 10

Refractive index of a Medium

Answer 10

Is the ratio of the sine of the angle of incidence to the sine of the angle of Refraction when light travels from a vacuum into that medium

n=sin(∅1)/ sin (∅2)

Question 11

Critical Angle

Answer 11

Is when light travels from a higher to a lower refractive medium,the angle of incidence whose corresponding angle of Refraction is 90°,is the critical angle

Question 12

Total Internal reflection

Answer 12

Is when light going from a higher to a lower refractive medium strikes the second medium with an angle of incidence greater than the critical angle and it does not enter the second medium;Instead it is all reflected back into the denser medium.

Question 13

Optical Fibre

Answer 13

Is a very things transparent rod(usually made of glass) through which light can travel by total internal reflection

Question 14

Short sight

Answer 14

Is where a person can see nearby objects clearly but cannot bring distant objects into focus.
The converging light rays fall short of the retina .
Cured by a concave lens

Question 15

Long sight

Answer 15

Is where a person can see distant objects clearly but cannot bring nearby objects into focus.
The lights rays converge long after the retina .
Cured by a convex lens.