MOVING COIL GALVANOMETER

Current sensitivity of a moving coil galvanometer is 5 div/mA and its voltage sensitivity (angular deflection per unit voltage applied) is 20 div/V. The resistance of the galvanometer is?

• 250 Ω
  

• 40 Ω

• 500 Ω

• 25 Ω

A moving coil galvanometer uses concave cylindrical magnetic poles, because

• It provides radial magnetic field

• The effective component of magnetic field is always normal to the area vector of the coil

• The galvanometer can use a linear scale for measurement

• angle dependence of torque can be avoided

ASSERTION(A): If a voltmeter is connected parallel to a resistor in a closed circuit the potential recorded.by the voltmeter is less than the p. d. across the resistor before connecting the voltmeter.

REASON (R): The total resistance of the circuit increases due to the introduction of the voltmeter .

• A & R are true and R is the correct explanation for A

• A & R are true but R is not the correct explanation for A

• Both A & R are false

• A is true but R is false

• A is false but R is true

The ratio of voltage sensitivity (  $V_s$ ) and current sensitivity ( $I_s$  ) of a moving coil galvanometer is (G =conductance)

•  $\frac{1}{G}$  

•  $\frac{1}{G^2}$  

•  $G$  

•  $G^2$  

A galvanometer of  $50ohm$  gives full scale deflection with 2mA current. To convert it into an ammeter ,the range of 10A is connected with it. What is the required value of shunt.

• 0.1 ohm

• 0.2 ohm

• 0.01 ohm

• 0.02 ohm

In moving coil galvanometer the deflection of the coil $\phi$  is related to the electric current I by the relation

•  $I\propto\tan\phi$  

•  $I\propto\phi$  

•  $I\propto\phi^2$  
  

•  $I\propto\tan^2\phi$  

The direction of the force on a current carrying wire placed in a magnetic field depends on

• direction off the current

• the direction of the field

• the direction of the field as well as the field

• neither the direction of current nor the direction of field

What is the principle of Moving Coil Galvanometer.

• Current carrying coil in an electric field experiences a force

• Current carrying coil in magnetic field experiences no force

• Current carrying conductor in magnetic field experiences a force

• Current carrying conductor in an electric field produces no force

The direction of the force on a current-carrying wire placed in a magnetic field depends on

• the direction of the current

• the direction of the field

• the direction of current as well as field

• neither the direction of current nor the direction of field

ASSERTION(A): Voltage sensitivity of moving coil galvanometer can be increased by increasing the number of turns of the coil of the galvanometer.

REASON (R): The voltage sensitivity of a moving coil galvanometer is directly proportional to number of turns of the coil of the galvanometer.

• A & R are true and R is the correct explanation for A

• A & R are true but R is not the correct explanation for A

• Both A & R are false

• A is true but R is false

• A is false but R is true