Ch 3 ( Geometrical Optics )

Question 1

Reflection of light

Answer 1

The light travelling in a medium falls on another medium bouces back in the first medium

Question 2

Laws of reflection of light

Answer 2

The incident ray, the normal and reflected ray at point of incidence, all lie on the same plane

Angle of incidence is equal to angle of reflection

Question 3

Types of reflection

Answer 3

2
Regular and irregular

Question 4

Concave mirror

Answer 4

A spherical mirror whose inner curved surface is reflecting

Question 5

Convex mirror

Answer 5

A spherical mirror whose outer curved surface is reflecting

Question 6

Spherical mirror

Answer 6

A mirror whose reflecting surface is part of a sphere

Question 7

Pole

Answer 7

Mid point of curved surface of mirror

Question 8

Centre of curvature

Answer 8

Centre of the sphere that the mirror is a part of

Question 9

Radius of curvature

Answer 9

Radius of sphere that the mirror is part of

Question 10

Principle axis

Answer 10

Line joining centre of curvature and the pole

Question 11

Principle focus of concave and convex

Answer 11

Concave real
Convex virtual

Question 12

Mirror formula

Answer 12

The relation between object distance, image distance, and focal length of mirror
1/f=1/p+1/q

P= object
Q= image

Question 13

Refraction of light

Answer 13

Bending of light as it passes from one medium to another is called refraction

Question 14

Laws of refraction

Answer 14

The incident ray, the normal and the refracted ray at the point of incident, all lie on the same plane

The ratio of the sine of angle of incident to the sine of angle of reflection is always equal to the constant=n

Question 15

Snells law

Answer 15

Sin <i/sine<r =constant = n

Question 16

Focal length

Answer 16

Distance from pole of mirror to principal focus

Question 17

Relation between focal length and radius

Answer 17

F=R/2 (concave)
F=-R/2 (covex)

Question 18

Refractive index

Answer 18

Ratio of speed of light in air “c” to speed of light in medium “v”
n=c/v

Question 19

Total internal reflection

Answer 19

When the angle of incidence becomes larger than the critical angle, no refractio occurs. All the light goes back into the denser medium.