The unit of reduction factor of the tangent galvanometer is
(1) Ampere
(2) Gauss
(3) Radian
(4) None of these
A voltmeter of resistance 1000 Ω gives full-scale deflection when a current of 100 mA flow through it. The shunt resistance required across it to enable it to be used as an ammeter reading 1 A at full-scale deflection is :
(1) 10000 Ω
(2) 9000 Ω
(3) 222 Ω
(4) 111 Ω
A galvanometer of \(50~\Omega \) resistance has 25 divisions. A current of 4 × 10–4 A gives a deflection of one division. To convert this galvanometer into a voltmeter having a range of 25 V, it should be connected with a resistance of:
1. 2500 Ω as a shunt
2. 2450 Ω as a shunt
3. 2550 Ω in series
4. 2450 Ω in series
A moving coil galvanometer of resistance 100Ω is used as an ammeter using a resistance 0.1Ω. The maximum deflection current in the galvanometer is 100 mA. Find the minimum current in the circuit so that the ammeter shows maximum deflection :
(1) 100.1 A
(2) 1000.1 mA
(3) 10.01 mA
(4) 1.01 mA
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
(1) 99995
(2) 9995
(3) 103
(4) 105
To make the field radial in a moving coil galvanometer :
(1) The number of turns in the coil is increased
(2) Magnet is taken in the form of horse-shoe
(3) Poles are cylindrically cut
(4) The coil is wounded on the aluminum frame
In a moving coil galvanometer, the deflection of the coil is related to the electrical current i by the relation
(1)
(2)
(3)
(4)
A moving coil galvanometer has N number of turns in a coil of effective area A, it carries a current I. The magnetic field B is radial. The torque acting on the coil is
(1)
(2)
(3)
(4)
Which among the following options needs to be decreased to increase the sensitivity of a moving coil galvanometer?
1. | the number of turns in the coil. | 2. | the area of the coil. |
3. | the magnetic field. | 4. | the couple per unit twist of the suspension. |
A ring of radius R, made of an insulating material carries a charge Q uniformly distributed on it. If the ring rotates about the axis passing through its center and normal to the plane of the ring with constant angular speed , then the magnitude of the magnetic moment of the ring is:
1. 2.
3. 4.