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Question
State the underlying principle of working of a moving coil galvanometer. Write two reasons why a galvanometer can not be used as such to measure current in a given circuit. Name any two factors on which the current sensitivity of a galvanometer depends.
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Solution
The underlying principle for the working of a moving coil galvanometer is that when a current-carrying conductor is placed inside a magnetic field, it experiences a magnetic force.
The two reasons why a galvanometer cannot be used for measuring current are
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The high resistance of galvanometer can disturb the original current flowing through the circuit
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The high current present in the circuit can destroy the coil windings present in the galvanometer
The factors on which the current sensitivity of a galvanometer depends are
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Number of turns in the coil
-
Torsional spring constant
-
Area of the coil
-
Strength of the magnetic field
(Any two can be taken as the answer)
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Reason (R): The resistance of the coil of the galvanometer increases on increasing the number of turns.
Select the most appropriate answer from the options given below:
