Welcome to your Electio magnetic induction and alternating currents-1
1.
A magnetic flux through a loop varies as ϕ = At³. If induced emf at t = 2 s is 24 V, the value of A is
2.
A square coil of side 20 cm and 800 turns rotates in a magnetic field. Induced emf: e = 150 sin(120πt). Magnetic field B is
3.
Two long parallel wires carry currents 40 A and 10 A in opposite directions. If magnetic repulsion per metre must balance a weight of 0.05 N/m, separation between wires is
4.
A conducting rod moves downward in a uniform magnetic field directed into the page. What is the direction of induced current?
5.
A magnet oscillates through a coil connected to a galvanometer. The deflection is
6.
Two wires carry currents in opposite directions. Force between them is
7.
A loop in a decreasing magnetic field will induce current that
8.
A disc rotates in a uniform magnetic field. EMF between rim and center is
9.
A loop enters a magnetic field region with constant velocity. Induced current exists
10.
A rod rotates in a magnetic field. EMF depends on
11.
Magnetic flux through a coil increases linearly with time. EMF is
12.
In a transformer, emf is induced because of
13.
A conductor rod falls freely in Earth’s magnetic field. Induced emf direction given by
14.
A loop shrinks in a magnetic field. The induced current
15.
A coil is rotated with double speed in same field. Max emf becomes
16.
A metal ring is placed near a solenoid whose current increases. Current in ring flows
17.
A loop in non-uniform magnetic field experiences
18.
A conductor moves parallel to magnetic field. EMF =
19.
Area of a coil decreases at 10⁻³ m²/s in a 0.2 T field. Induced emf =
20.
A coil rotates in a magnetic field. At what angle is induced emf zero?
21.
Magnetic flux = 5 + 2t Wb. EMF = ?
22.
A conductor rod of length L moves in B at 30° angle. EMF = ?
23.
A loop moves completely inside a uniform magnetic field. EMF =
24.
A magnet is slowly taken away from a coil. Induced current direction will
25.
Magnetic field inside coil decreases. Induced current will produce field
26.
A loop enters magnetic field region faster. Induced emf becomes
27.
A ring is cut and ends separated slightly. Induced current becomes
28.
A disc rotates faster. Induced emf between rim and center becomes
29.
A solenoid’s current decreases. A nearby ring’s induced current is
30.
A square coil is stretched increasing its area in a uniform B field. EMF is
31.
In a transformer, ratio of voltages depends on
32.
A loop is rotated with constant ω. Induced emf waveform is
33.
A rod falls freely. Induced emf increases because
34.
A closed loop approaches a bar magnet’s north pole. Induced current direction is
35.
A circular loop is placed in a magnetic field perpendicular to its plane. If its radius increases uniformly, the induced current will be
36.
A metal rod of length 0.5 m moves with speed 6 m/s perpendicular to a 0.4 T magnetic field. Induced emf = ?
37.
A current loop is pulled out of a magnetic field. The induced current direction is such that it
38.
A conducting disc rotates in a uniform magnetic field. The induced emf between center and rim is proportional to
39.
A wire loop is kept stationary, and magnetic field passing through it decreases with time. The induced current will be
40.
A magnetic flux varies as ϕ = 4t². Induced emf at t = 1 s is
41.
A coil of 200 turns rotates in a 0.5 T field. Area = 0.04 m². Angular speed = 50 rad/s. Max emf?
42.
A straight rod moves perpendicular to a 0.3 T field with 5 m/s, length 0.6 m. EMF = ?
43.
A square loop is pulled out of a magnetic field. Induced current direction?
44.
A coil is connected to a galvanometer. Magnet pushed into coil. Deflection?
45.
A magnet oscillates through a coil. Galvanometer shows
