Optics concepts

Question 1

2 Conditions for interference?

Answer 1

monochromatic light & mutual coherence

Question 2

The condition for Bright fringes

Answer 2

constructive Interference

Question 3

The condition for Dark fringes

,

Answer 3

(destructive Interference)

Question 4

Interference obeys the law of ___________

Answer 4

conservation of energy

Question 5

For a fixed wavelength λ,
the fringes are ____ when the slits are closer together
(____d).

Answer 5

wider

small

Question 6

For a fixed wavelength λ,

The fringes are _______when the slits are far apart (____ d).

Answer 6

narrow finer

large

Question 7

Interference at different slit differences

In bright fringes the Narrower the slit distance,_____ the angle

Answer 7

greater

Question 8

For a fixed slit separation (fixed __),
the fringes are wider for a ______
wavelength λ.

Hence, red fringes are__________ than blue fringes.

.

Answer 8

d

longer

spread out
farther

Question 9

Thus, for white light illumination,

interference fringes are

Answer 9

colored

Question 10

Interference in Liquid medium
The condition for Bright fringe,

Angle (θ) or spacing between m=0 & m=1 Water will be _______.

Answer 10

smaller

Question 11

Interference in Liquid medium
The condition for Bright fringe,

The fringe width(y) decreases as
wavelength(λ) gets ______, y α λ

Answer 11

reduced

Question 12

The color of oil slicks on the wet roads and the colored

fringes in soap bubbles is caused by

Answer 12

Thin Film Interference

Question 13

• Thin film interference due to ________________

This is ‘wave effect.’

Answer 13

Multiple reflection processes.

Question 14

For a thin film, ________light is long

enough to cause interference effect

Answer 14

coherence length of ordinary

Question 15

Thin Film Interference are based on

two conditions…

Answer 15

• path difference

- phase change

Question 16

Phase Reversal :

180° Phase change happens when light travelling in
_______RI medium reflects of ______ RI medium.

Answer 16

lower

higher

Question 17

Principle of Optical Reversibility: In the absence of any absorption, a
light ray that is reflected or refracted will _____________if its
direction is reversed.

Answer 17

retrace its original path