Advertisements
Advertisements
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.
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
-
The high resistance of galvanometer can disturb the original current flowing through the circuit
-
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
-
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)
APPEARS IN
RELATED QUESTIONS
A rectangular coil of a moving coil galvanometer contains 50 turns each having area 12 cm2 . It is suspended in radial magnetic field 0.025 Wb/m2 by a fibre of twist constant 15 x10-10 Nm/degree. Calculate the sensitivity of the moving coil galvanometer.
Obtain the expression for current sensitivity of moving coil galvanometer.
A moving coil galvanometer has a resistance of 25Ω and gives a full scale deflection for a current of 10mA. How will you convert it into a voltmeter having range 0 - 100 V?
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.
State the principle of the working of a moving coil galvanometer, giving its labeled diagram ?
State how a moving coil galvanometer can be converted into an ammeter.
Define the term 'current sensitivity' of a moving coil galvanometer.
The deflection in a moving coil galvanometer is ______.
A moving coil galvanometer has 150 equal divisions. Its current sensitivity is 10-divisions per milliampere and voltage sensitivity is 2 divisions per millivolt. In order that each division reads 1 volt, the resistance in ohms needed to be connected in series with the coil will be ______.
To convert a moving coil galvanometer into an ammeter we need to connect a ______.
