light

Question 1

first law of reflection

Answer 1

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

Question 2

second law of reflection

Answer 2

angle of incidence is equal to angle of reflection (i=r)

Question 3

refraction

Answer 3

bending of light as light passes from one optical medium to another

Question 4

first law of refraction

Answer 4

incident ray, refracted ray and normal all lie in the same plane

Question 5

second law of refraction
snell’s law

Answer 5

for two given media the ratio of the sine of angle of incidence to the sine of angle of refraction is a constant (n=sin i/sin r)

Question 6

refractive index (n)

Answer 6

ratio of speed of light in vacuum to the speed of light in the medium

Question 7

critical angle (c)

Answer 7

angle of incidence in an optically denser medium for which angle of refraction in the optically less dense medium is 90 degrees

Question 8

total internal reflection

Answer 8

complete reflection of a light ray inside an optically denser medium at its boundary with an optically less dense medium

Question 9

focal length

Answer 9

distance between the optical centre and the focal point