wave_mechanics critical_thinking Question 31
Question: A metal wire of linear mass density of 9.8 g/m is stretched with a tension of 10 kg weight between two rigid supports 1 metre apart. The wire passes at its middle point between the poles of a permanent magnet, and it vibrates in resonance when carrying an alternating current of frequency n. The frequency n of the alternating source is
[AIEEE 2003]
Options:
A) 25 Hz
B) 50 Hz
C) 100 Hz
D) 200 Hz
Show Answer
Answer:
Correct Answer: B
Solution:
In condition of resonance, frequency of a.c.
will be equal to natural frequency of wire $ n=\frac{1}{2l}\sqrt{\frac{T}{m}}=\frac{1}{2\times 1}\sqrt{\frac{10\times 9.8}{9.8\times {{10}^{-3}}}}=\frac{100}{2}=50 $
$ Hz $
BETA
