There is a uniform magnetic field directed perpendicular and into the plane of the paper. An irregular shaped conducting loop is slowly changing into a circular loop in the plane of the paper. Then,
(a) Current is induced in the loop in the anti-clockwise direction
(b) Current is induced in the loop in clockwise direction
(c) AC Current is induced in the loop
(d) No current is induced in the loop
(a) Current is induced in the loop in the anti-clockwise direction
(b) Current is induced in the loop in clockwise direction
(c) AC Current is induced in the loop
(d) No current is induced in the loop
(a) Current is induced in the loop in the anti-clockwise direction
Two currents loops are concentric and lie in the same plane. The current in the outer loop is anti clockwise and increasing with time. The induced current in the inner loop ,is
(a) Clockwise
(b) Zero
(c) Counter-clockwise
(d) None of these
A square loop of side l , resistance R is placed in a uniform magnetic field B acting normally to the plane of the loop. If we attempt to pull it out of the field with a constant velocity v , then the power needed is
(a) BRlv
(b) B²l²v²/R
(c) B l²v²/ R
(d) Blv/R
A coil of N turns and mean cross-sectional area A is rotating with uniform angular velocity ω about an axis at right angle to uniform magnetic field B. The induced emf in the coil will be
(a) NBAsinωt
(b) NBωsinωt
(c) NB/Asinωt
(d) NBAωsinωt
The self inductance of long solenoid cannot be increased by
(a) increasing its area of cross section
(b) increasing its length
(c) changing the medium with grater permeability
(d) Increasing the current through it.
The magnetic flux linked with a coil is given by an equation Φ = 5t² + 2t + 3. The induced e.m.f. in the coil at the third second will be
(A) 32 units
(B) 54 units
(C) 40 units
(D) 65 units
A conducting rod of unit length moves with a velocity 10 m/s in a direction perpendicular to its length and perpendicular to a uniform magnetic field of magnitude 0.2 T. The emf induced between the ends of the rod is
(a) 4 V
(b) 2V
(c) 1V
(d) Zero
In a circuit with a coil of resistance 3Ω, the magnetic flux changes from 1.0 Wb to 10.0 Wb in 0.3 s. The charge that flows in the coil during this time is
(a) 2.0 C
(b) 3.0 C
(c) 4.0 C
(d) 1.0 C
The V-i graph for a conductor at temperature T¹ and T² are as shown in the figure. (T² - T¹) is proportional to
(a) cos θ
(b) sin θ
(c) cot 2θ
(d) tan θ
Twenty-seven drops of mercury are charged simultaneously to the same potential of 10 volts. What will be potential if all the charged drops are made to combine to form one large drop ?
(a) 180 V
(b) 90 V
(c) 120 V
(d) 45 V
What is the shape of the magnet in Moving Coil Galvanometer to make the torque maximum?
a) Horse Shoe
b) Convex
c) Concave
d) None of these.
In a region of constant potential,
(a) the electric field is uniform
(b) the electric field is zero
(c) there can be no charge inside the region
(d) the electric field shall necessarily change, if a charge is placed outside the region
The direction of magnetic dipole moment is always from
a) North pole to south pole
b)Away from North pole outside magnet
c) South pole to North Pole
d) all of the above
A screen is placed 50m from a single slit, which is illuminated with 6000Å light. If the distancebetween the first and third minima in the diffraction pattern is 3.00mm, what is the width of the slit ?
i. 200 µm
ii. 300 µm
iii. 250 µm
iv. 350 µm