If a loop in a basic dc generator suddenly begins rotating at a faster speed, the induced voltage
remains unchanged
reverses polarity
increases
decreases
no correct answer
If an electron moves perpendicular to the uniform magnetic field of magnitude 0.35 T with the speed equal to 4.69×106, what is the radius of its circular orbit? (me = 9.11×10-31kg)
7.63×104
7.63×10-5
7.63×106
0.73×10-6
7.3×10-6
Calculate the maximum kinetic energy of protons in a cyclotron of radius 0.50 m in a magnetic field of 0.35 T.
1.46 KeV
1.46 meV
1.46 MeV
0.146 eV
1.46 eV
A rectangular copper strip 1.5 cm wide and 0.1 cm thick carries a current of 5 A. A 1.2 T magnetic field is applied perpendicular to the strip. Find the Hall voltage that should be produced.
0.442 µV
0.442 mV
4.42 V
44.2 V
4.42 mV
A toroidal winding carrying a current of 5 A is wound with 300 turns/m of wire. The core is iron, which has a magnetic permeability of 5000µ0 under the given conditions. Find H inside the iron core.
1500
150
15
1.5
0.15
A toroidal winding carrying a current of 5 A is wound with 300 turns/m of wire. The core is iron, which has a magnetic permeability of 5000µ0 under the given conditions. Find B inside the iron core.
9.43
T9.43
T0.943 T
9.43 T
943 T
Assume that a motor having coils with a resistance of 10 Ohm is supplied by a voltage of 120 V. When the motor is running at its maximum speed, the back emf is 70V. Find the current in the coils when the motor is first turned on.
10 A
12 A
1 A
1.2 A
120 A
Assume that a motor having coils with a resistance of 10 Ohm is supplied by a voltage of 120 V. When the motor is running at its maximum speed, the back emf is 70 V. Find the current in the coils when the motor has reached maximum speed.
3 A
4 A
5 A
6 A
7 A
Calculate the inductance of a solenoid containing 300 turns if the length of the solenoid is 25 cm and its cross-sectional area is 4 cm2.
0.181 mH
0.181 H
1.81 mH
1.81 H
181 H
Calculate the self-induced emf in the solenoid containing 300 turns if the length of the solenoid is 25 cm and the current through it is decreasing at the rate of 50 A/s.
0.905 mV
9.05 mV
0.905 V
9.05 V
905 V
Calculate the time constant of RL circuit consisting of a 30 mH inductor in series with 6 Ω resistor and 12 V battery.
180 ms
60 ms
5 ms
2 ms
30 ms