CBSE
If a coil of 40 turns and area 4.0 cm2 is suddenly removed from a magnetic field, it is observed that a charge of 2.0 x 10-4 C flows into the coil. If the resistance of the coil is 80 Ω, the magnetic flux density in Wb/m2 is
0.5
1.0
1.5
2.0
The magnetic flux linked with the coil varies with time as = 3 t2 + 4 t + 9. The magnitude of the induced emf at 2 s is
9 V
16 V
3 V
4 V
The magnetic flux through a loop of resistance 10 Ω is given by (=5t2 − 4t+ 1 Wb). How much current is induced in the loop after 0.2 s ?
0.4 A
0.2 A
0.04 A
0.02 A
The magnetic flux linked with a coil at any instant t is given by the equation : = 5t3 − 100t + 300. The magnitude of emf induced in the coil after 3 s is
10 V
20 V
35 V
70 V
A coil having an inductance of 0.5 H carries a current which is uniformly varying from 0 to 10 A in 2s. The emf (in volts) generated in the coil is
10
5
2.5
1.25
The magnetic flux linked with a coil satisfies the relation Wb, where t is the time in second. The emf induced in the coil at t = 2 s is
22 V
18 V
16 V
40 V
A coil of self-inductance L is connected in series with a bulb B and an AC source. Brightness of the bulb decreases when
frequency of the AC source is decreased
number of turns in the coil is reduced
a capacitance of reactance XC =XL is included in the same circuit
an iron rod is inserted in the coil
In 0.1 s, the current in a coil increases from 1 A to 1.5 A. If inductance of coil is 60 mH, then induced current in external resistance of 3Ω will be
1 A
0.5 A
0.2 A
0.1 A
The current through a coil of self-inductance L = 2mH is given by i = t2e-t at time t. How long it will take to make the emf zero ?
1 s
2 s
3 s
4 s
Lenz's law of electromagnetic induction corresponds to the
law of conservation of charge
law of conservation of energy
law of conservation of momentum
law of conservation of angular momentum