### NEET Physics - New - Electromagnetic Induction and Alternating Currents

#### Question - 1

A metallic rod of mass per unit length 0.5 kg/m is lying horizontally on a smooth inclined plane which makes an angle of 30° with the horizontal. The rod is not allowed to slide down by flowing a current through it when a magnetic field of induction 0.25 T is acting on it in the vertical direction. The current flowing in the rod to keep is stationary is :

• A 7.14 A
• B 5.98 A
• C 14.76 A
• D 11.32

#### Question - 2

Two cities are 150 km apart. Electric power is sent from one city to another city through copper wires. The fallof potential per km is 8 volt and the average resistance per km is 0.5Ω. The power loss in the wire is:

• A 19.2 W
• B 19.2 kW
• C 19.2 J
• D 12.2 kW

#### Question - 3

A thin semicircular conducting ring (PQR) of radius 'r' is falling with its plane vertical in a horizontal magnetic field B, as shown in figure. The potential difference developed across the ring when its speed is v, is :

• A Zero
• B Bvπr2/2 and P is at higher potential
• C πrBv and R is at higher potential
• D 2rBv and R is at higher potential

#### Question - 4

In a coil of resistance 10Ω the induced current developed by changing magnetic flux through it, is shown in figure as a function of time. The magnitude of change in flux through the coil in Weber is :

• A 8
• B 2
• C 6
• D 4

#### Question - 5

A thin ring of radius R meter has charge q coulomb uniformly spread on it. The ring rotates about its axis with a constant frequency of f revolutions/so The value of magnetic induction in Wb/m2 at the centre of the ring is :

• A μ0qf/2πR
• B μ0q/2πfR
• C μ0q/2fR
• D μ0qf/2R

#### Question - 6

A particle of mass m, charge Q and kinetic energy T enters a transverse uniform magnetic field of induction B. After 3 seconds the kinetic energy of the particle will be :

• A 4 T
• B 3 T
• C 2 T
• D T

#### Question - 7

A coil of inductance 300 mH and resistance 2 Ω is connected to a source of voltage 2 V. The current reaches half of its steady state value in :

• A 0.05 s
• B 0.1 s
• C 0.15 s
• D 0.2 s

#### Question - 8

The self inductance of the motor of an electric fan is 10 H. In order to impart maximum power at 50 Hz, it should be connected to a capacitor of capacitance:

• A 4 μF
• B 8 μF
• C 1 μF
• D 2 μF

#### Question - 9

The magnetic flux linked with a coil, in webers, is given by the equations φ=3t2+4t+9. Then the magnitude of induced e.m.f. at t = 2 second will be:

• A 2 volt
• B 4 volt
• C 8 volt
• D 16 volt

#### Question - 10

A copper ring is held horizontally and a bar magnet is dropped through the ring with its length along the axis of the ring. The acceleration of the falling magnet while it is passing through the ring is :

• A Equal to that due to gravity
• B Less than that due to gravity
• C More than that due to gravity
• D Depends on the diameter of the ring and the length of the magnet