current-electricity Question 55
Question: Q. 9. With the help of the circuit diagram, explain the working principle of metre bridge. How is it used to determine the unknown resistance of a given wire? Write the necessary precautions to minimize the error in the result.
R [O.D. I, II, III 2015]
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Solution:
Ans. The circuit diagram of the metre bridge is as shown below :
Working Principle : The working principle of the meter bridge is the same as that of a wheatstone bridge. The Wheatstone bridge gets balanced when :
For the meter bridge, circuit shown above, this relation takes the form
Determination of unknown Resistance
We find the value of the balancing length
Calculation of
By choosing (at least three) different value of
(i) Make all contacts in a neat, clean and tight manner .
(ii) Select those values of
[Any one]
