A coil of inductance 8.4 mH and resistance 6 is connected to a 12 V battery. The current in the coil is 1.0 A at approximately the time.
1. 500 ms
2. 20 ms
3. 35 ms
4. 1 ms
PQ is an infinite current carrying conductor. AB and CD are smooth conducting rods on which a conductor EF moves with constant velocity v as shown. The force needed to maintain constant speed of EF is –
1.
2.
3.
4.
A 50 turns circular coil has a radius of 3 cms, it is kept in a magnetic field acting normal to the area of the coil. The magnetic field B increased from 0.10 tesla to 0.35 tesla in 2 milliseconds. The average induced emf in the coil is-
1. 1.77 volts
2. 17.7 volts
3. 177 volts
4. 0.177 volts
A semicircular wire of radius R is rotated with constant angular velocity about an axis passing through one end and perpendicular to the plane of the wire.
There is a uniform magnetic field of strength B. The induced emf between the ends is -
1.
2.
3. is variable
4. none of these
The inductance of a closed-packed coil of 400 turns is 8 mH. A current of 5 mA is passed through it. The magnetic flux through each turn of the coil is approximately-
1.
2.
3.
4.
Loop A of radius (r << R) moves towards loop B with a constant velocity v in such a way that their planes are always parallel.
What is the distance (x) between the two loops when the induced emf in loop A is maximum –
1.
2.
3.
4.
The magnetic flux through each turn of a 100 turn coil is , where t is in second. The induced emf at t = 2 s is
1.
2.
3.
4.
A copper rod of length 0.19 m is moving parallel to a long wire with a uniform velocity of 10 m/s. The long wire carries 5 ampere current and is perpendicular to the rod. The ends of the rod are at distances 0.01 m and 0.2 m from the wire. The emf induced in the rod will be-
1.
2.
3.
4.
Rate of increment of energy in an inductor with time in series LR circuit getting charge with battery of emf E is best represented by – [inductor has initially zero current]
1.
2.
3.
4.
A long solenoid having 1000 turns per cm is carrying alternating current of one ampere peak value. A search coil of area of cross-section and of 20 turns is placed in the middle of the solenoid so that its plane is perpendicular to the axis of the solenoid. The search coil registers a peak voltage . The frequency of the current in the solenoid is -
1. 1.6 per second
2. 0.16 per second
3. 15.9 per second
4. 15.85 per second