1. (JEE Main 2024 (Online) 1st February Morning Shift)
A rectangular loop of sides
and
,
with its sides parallel to the
-axis
and
-axis
respectively, moves with a velocity of
in the positive
axis direction, in a space containing a variable magnetic field in the positive
direction. The field has a gradient of
along the negative
direction and it is decreasing with time at the rate of
.
If the resistance of the loop is
,
the power dissipated by the loop as heat is __________
.
Correct answer is 216
is the magnetic field at origin
Motional emf in
Motional emf in
Motional emf in
Magnetic field on rod BC B
Motional emf in
For time variation
2. (JEE Main 2024 (Online) 30th January Morning Shift)
A ceiling fan having 3 blades of length
each is rotating with an angular velocity of 1200
. The magnetic field of earth in that region is
and angle of dip is
. The emf induced across the blades is
. The value of
is _________.
Correct answer is 32
3. (JEE Main 2024 (Online) 29th January Evening Shift)
A horizontal straight wire
long extending from east to west falling freely at right angle
to horizontal component of earths magnetic field
. The instantaneous value of emf induced in the wire when its
velocity is
is _________
.
Correct answer is 3
4. (JEE Main 2023 (Online) 8th April Evening Shift
)
An emf of
is induced in a metal rod of length
held normal to a uniform magnetic field of
, when moves with a velocity of:
A.
B.
C.
D.
Correct Option is (B)
The emf induced in a rod moving through a magnetic field is given by Faraday's law of
electromagnetic induction, specifically, in the form of motional emf, which states that:
where:
(B) is the magnetic field strength,
(L) is the length of the rod, and
(v) is the velocity of the rod.
In this case, we are given the emf, (B), and (L), and we need to solve for (v). Rearranging the
equation gives:
Substituting the given values:
5. (JEE Main 2023 (Online) 25th January Evening Shift)
A wire of length 1m moving with velocity 8 m/s at right angles to a magnetic field of 2T. The magnitude of
induced emf, between the ends of wire will be __________.