Diffraction Quiz 1

Question 1

Fill in the blanks: Interference deals with the interaction of two different waves whereas diffraction deals with the interaction of two different _. Strength of bright lines in interference pattern are _ whereas strength of bright lines in diffraction pattern are _. In interference pattern, there is _ contrast between bright and dark lines whereas in diffraction pattern, there is _ contrast between bright and dark lines.

Accepted Answer

waves, secondary wavelets, equal, not equal, rich, poor

Answer

waves, primary wavelets, equal, not equal, rich, poor

Answer

secondary wavelets, waves, not equal, equal, rich, poor

Answer

primary wavelets,waves, equal, not equal, rich, poor

Question 2

An optician sees a prescription and selects the best available option for an eye patient after making him observe light of wavelength $$5900\overset{\circ}{\mathop{	ext{A}}}\,$$ through a small opening of $$1.5	ext{ mm}$$ with the help of a lens. The optician is taking advantage of rectilinear nature of light waves primarily because the wavelength used is small and secondarily because the diffraction becomes effective only after a distance of

Accepted Answer

$$3.8	ext{ m}$$

Answer

$$2.4	ext{ m}$$

Answer

$$2.8	ext{ m}$$

Answer

$$3.4	ext{ m}$$

Question 3

Determine the magnitude of difference in angular spread for fourth secondary minimum and that for second secondary minimum for the diffraction response of a wave of $$5000	imes {{10}^{-10}}	ext{ m}$$ through a hole of $$3	ext{ mm}$$ size.

Accepted Answer

$$3.33	imes {{10}^{-7}}$$

Answer

$$2.33	imes {{10}^{-6}}$$

Answer

$$5.33	imes {{10}^{-5}}$$

Answer

$$1.33	imes {{10}^{-8}}$$

Question 4

Choose the correct option: In diffraction, the ratio between width and angular width of central maximum gives  $$ \ $$ $$(A)$$ focal length of lens attached to the slit $$ \ $$ $$(B)$$ wavelength of the light used $$ \ $$ $$(C)$$ distance of screen from the slit  $$ \ $$ $$(D)$$ size of the slit

Accepted Answer

A and C

Answer

A and B

Answer

C and D

Answer

B and D

Question 5

The displacement between the first two dark lines on each side of the diffraction response of light of certain frequency when passed through a slit on a screen, kept at $$6	ext{ m}$$ from the slit is $$3.88	imes {{10}^{-3}}	ext{ mm}$$. Evaluate the angular spread of central maximum.

Accepted Answer

$$6.4	imes {{10}^{-4}}	ext{ rad}$$

Answer

$$2.1	imes {{10}^{-4}}	ext{ rad}$$

Answer

$$2.4	imes {{10}^{-3}}	ext{ rad}$$

Answer

$$6.1	imes {{10}^{-3}}	ext{ rad}$$