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प्रश्न
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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उत्तर
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
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Torsional spring constant
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Area of the coil
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Strength of the magnetic field
(Any two can be taken as the answer)
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संबंधित प्रश्न
Why does a galvanometer show a momentary deflection at the time of charging or discharging a capacitor? Write the necessary expression to explain this observation.
Obtain the expression for current sensitivity of moving coil galvanometer.
Why is it necessary to introduce a radial magnetic field inside the coil of a galvanometer?
Why does a galvanometer when connected in series with a capacitor show a momentary deflection, when it is being charged or discharged?
How does this observation lead to modifying the Ampere's circuital law?
Hence write the generalised expression of Ampere's law.
Explain, giving reasons, the basic difference in converting a galvanometer into (i) a voltmeter and (ii) an ammeter?
Draw a labelled diagram of a moving coil galvanometer and explain its working. What is the function of radial magnetic field inside the coil?
When a galvanometer is shunted with a 4 Ω resistance, the deflection is reduced to one-fifth. If the galvanometer is further shunted with a 2 Ω wire. The further reduction (find the ratio of decrease in current to the previous current) in the deflection will be (the main current remains the same)
A galvanometer coil bas 500 turns and each tum has an average area of 3 × 10-4 m2. If a torque of 1.5 Nm is required to keep this coil parallel to a magnetic field when a current of 0.5 A is flowing through it, the strength of the field (in T) is ______.
To convert a moving coil galvanometer into an ammeter we need to connect a ______.
The figure below shows a circuit containing an ammeter A, a galvanometer G and a plug key K. When the key is closed:
