Question 218: Waves

Question

An observer moves towards a stationary source of sound, with a velocity one-fifth of the velocity of sound. What is the percentage increase in the apparent frequency ?

Accepted Answer

$$n' = n\left[ {{{v + {v_0}} \over v}} ight] = n\left[ {{{v + {v \over 5}} \over v}} ight] = n\left[ {{6 \over 5}} ight]$$
$${{n'} \over n} = {6 \over 5};{{n' - n} \over n}$$
$$ = {{6 - 5} \over 5} 	imes 100 = 20\% $$

Answer

$$0.5\% $$

Answer

zero

Answer

$$20\% $$

Answer

$$5\% $$

Waves

An observer moves towards a stationary source of sound, with a velocity one-fifth of the velocity of sound. What is the percentage increase in the apparent frequency ?

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