Wave interference Quiz 1

Question 1

A cyclist fitted two bells in his bicycle for different purposes of his choice. If the beat frequency they project is $$6	ext{ Hz}$$ and if one of the bells rings with a frequency equal to $$160	ext{ Hz}$$, evaluate the frequency with which the other bell rings.

Accepted Answer

$$154	ext{ Hz}$$

Answer

$$160	ext{ Hz}$$

Answer

$$-166	ext{ Hz}$$

Answer

$$-154	ext{ Hz}$$

Question 2

The ratio of amplitude of the resultant wave of a constructive interferogram to the amplitude of one of the waves which interfere with the other wave to produce this interferogram is

Accepted Answer

$$2$$

Answer

$$1$$

Answer

$$-1$$

Answer

$$-2$$

Question 3

The interferogram of two waves looks like a rope tied tightly to two different poles. This is clearly a case of __ interference. Here, the _ of the first wave is in sync with the _ of the other wave while the _ of the first wave is in sync with the _ of the other wave.

Accepted Answer

destructive; peak; valley; valley; peak

Answer

destructive; peak; valley; peak; valley

Answer

destructive; valley; peak; valley; peak

Answer

constructive; valley; peak; valley; peak

Question 4

Suppose that two plane waves of equal frequencies interact with each other at a particular angle. What can be said about the spacing between two lines in the interferogram of their interaction? If this equal frequency of two waves is $$2	imes {{10}^{8}}	ext{ Hz}$$ and if these waves interact perpendicularly, what is the spacing between two adjacent lines in their interferogram?

Accepted Answer

fringe spacing increases with decreasing angle; $$1.5	ext{ m}$$

Answer

fringe spacing decreases with decrease in frequency; $$1.5	ext{ m}$$

Answer

fringe spacing decreases with decreasing angle; $$0.5	ext{ m}$$

Answer

fringe spacing increases with decrease in frequency; $$0.5	ext{ m}$$

Question 5

Two mirrors are used to reflect the light rays coming from the same monochromatic source. Suppose these reflected rays interfere with each other and let their interaction be recorded on a screen. Now, if the position of one of the mirrors is changed by $$0.002	ext{ mm}$$ to see that bright and dark fringes in their interference pattern change into each other $$52$$ times, determine the number of times these rays propagate in a second.

Accepted Answer

$$1.9	imes {{10}^{15}}	ext{ Hz}$$

Answer

$$1.3	imes {{10}^{14}}	ext{ Hz}$$

Answer

$$1.6	imes {{10}^{14}}	ext{ Hz}$$

Answer

$$1.2	imes {{10}^{15}}	ext{ Hz}$$