wave_mechanics critical_thinking Question 18
Question: A light pointer fixed to one prong of a tuning fork touches a vertical plate. The fork is set vibrating and the plate is allowed to fall freely. If eight oscillations are counted when the plate falls through 10 cm, the frequency of the tuning fork is
[IIT 1977; KCET 2002]
Options:
A) 360 Hz
B) 280 Hz
C) 560 Hz
D) 56 Hz
Show Answer
Answer:
Correct Answer: D
Solution:
Time of fall = $ \sqrt{\frac{2h}{g}} $
$ =\sqrt{\frac{2\times 10}{1000}}=\frac{1}{\sqrt{50}} $ In this time number of oscillations are eight.
So time for 1 oscillation =$ \frac{1}{8\sqrt{50}} $ Frequency =$ 8\sqrt{50}Hz $ = 56$ Hz $
BETA
