class 8 optics

An object which produces its own light is called ………………source

• luminous

• transparent

• non-luminous

• opaque

Materials which don’t allow light to pass through them are called…………………

• luminous

• transparent

• non-luminous

• opaque

The complete dark region of the shadow is called……………………

• penumbra

• umbra

• translucent

• non-luminous

.............. is the perpendicular line to the point where the light strikes the boundary

• incident

• reflected

• refracted

• normal

The number of images between two mirrors depends upon

• mirror

• image

• angle

The effect of bending of light is called

• reflection

• refraction

• light

• normal

Speed of light in air is …………………. Km/s

• 300000

• 200000

• 250000

• 100000

When the angle of refraction is 90⁰, the angle of incidence is ...........angle

• reflected

• refracted

• critical

• total internal reflection

The angle between the normal and reflected ray is........angle

• reflected

• refracted

• critical

………....occurs when the angle of incidence is greater than the critical angle

• total internal reflection

• reflection

• refraction

• none of them