Question:
A metal wire of linear mass density of 9.8 g/m is stretched with a tension of 10 kg-wt between two rigid supports 1 m 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
A metal wire of linear mass density of 9.8 g/m is stretched with a tension of 10 kg-wt between two rigid supports 1 m 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
Updated On: Jul 5, 2022
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The Correct Option is A
Solution and Explanation
The wire will vibrate with the same frequency as that of source. This can be considered as an example of forced vibration. $ T=10\times 9.8N=98N $ $ m=9.8\times {{10}^{-3}}kg/m $ Frequency of wire $ f=\frac{1}{2L}\sqrt{\left( \frac{T}{m} \right)} $ $ =\frac{1}{2\times 1}\sqrt{\left( \frac{98}{9.8\times {{10}^{-3}}} \right)} $ $ =50\,\,Hz $
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Concepts Used:
Electromagnetic waves
The waves that are produced when an electric field comes into contact with a magnetic field are known as Electromagnetic Waves or EM waves. The constitution of an oscillating magnetic field and electric fields gives rise to electromagnetic waves.
Types of Electromagnetic Waves:
Electromagnetic waves can be grouped according to the direction of disturbance in them and according to the range of their frequency. Recall that a wave transfers energy from one point to another point in space. That means there are two things going on: the disturbance that defines a wave, and the propagation of wave. In this context the waves are grouped into the following two categories:
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