Lenses

Question 1

Eye defect

Answer 1

Long sight: Hyperopia Long Sight Convergence corrected by Lens Convex Converging, lens too weak eyeball too short

Short sight: Short Sight Diverging Myopia corrected by Lens Concave Diverging, lens too strong eyeball too long

Question 2

Dispersion of light

Answer 2

Happens when different colours travel at different speed in different media

Red deviates least as it has the least change in speed & has greatest velocity in glass, violet deviates most as it has the most change in speed & has slowest velocity in glass

Question 3

Reflection of light

Answer 3

Refraction: The bouncing of light

Electromagnetic spectrum; Radio, microwaves, infrared, light, ultraviolet, x-rays, gamma

Angle i & r are measured from the normal

Question 4

Refraction

Answer 4

Refraction happens due to change in the speed of light due to change in medium

Velocity gas > velocity liquid > velocity solid

Less dense media to more dense media means the ray bends towards the normal

More dense media to less dense media means the ray bends away from the normal

Question 5

Applications of TIR

Answer 5

TIR = Total Internal Reflection

Periscope, fibre optic

Question 6

Critical angle & total internal reflection

Answer 6

Below critical angle = reflected ray + weak refracted ray

At critical angle = reflected ray + refracted ray at 90 degrees

Beyond critical angle = strong reflected ray + no refracted ray