Physics-
General
Easy
Question
As shown in the figure a metal rod makes contact and complete the circuit. The circuit is perpendicular to the magnetic field with 
If the resistance is 
, force needed to move the rod as indicated with a constant speed of 
is
N
N
The correct answer is: N
Induced current in the circuit 
Magnetic force acting on the wire 
External force needed to move the rod with constant velocity
Related Questions to study
physics-
As shown in the figure, P and Q are two coaxial conducting loops separated by some distance. When the switch S is closed, a clockwise current 
flows in P (as seen by E) and an induced current 
flows in Q. The switch remains closed for a long time. When S is opened, a current 
flows in Q. Then the directions of and (as seen by E) are
As shown in the figure, P and Q are two coaxial conducting loops separated by some distance. When the switch S is closed, a clockwise current flows in P (as seen by E) and an induced current flows in Q. The switch remains closed for a long time. When S is opened, a current flows in Q. Then the directions of and (as seen by E) are
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A particle moves along a line by 
then S is decreasing when t 
A particle moves along a line by then S is decreasing when t
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Assertion: f(x) = ln 
is an odd function.
Reason: Let f be a function with domain D such that
i) x D 
– x D
ii) f(–x) = – f(x) and
iii) f (0) = 0 or f (0) is not defined
Then the function f(x) is an odd function
Assertion: f(x) = ln is an odd function.
Reason: Let f be a function with domain D such that
i) x D – x D
ii) f(–x) = – f(x) and
iii) f (0) = 0 or f (0) is not defined
Then the function f(x) is an odd function
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A conducting rod of length 2l is rotating with constant angular speed w about its perpendicular bisector. A uniform magnetic field 
exists parallel to the axis of rotation. The e.m.f. induced between two ends of the rod is
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A metallic square loop ABCD is moving in its own plane with velocity v in a uniform magnetic field perpendicular to its plane as shown in the figure. An electric field is induced
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Two circular coils can be arranged in any of the three situations shown in the figure. Their mutual inductance will be
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A uniform but time-varying magnetic field B(t) exists in a circular region of radius a and is directed into the plane of the paper, as shown. The magnitude of the induced electric field at point P at a distance r from the centre of the circular region
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With the usual meaning for a, b, c and s if 
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Consider the situation shown in the figure. The wire AB is sliding on the fixed rails with a constant velocity. If the wire AB is replaced by semicircular wire, the magnitude of the induced current will
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A thin semicircular conducting ring of radius R is falling with its plane vertical in a horizontal magnetic induction B. At the position MNQ, the speed of the ring is V and the potential difference developed across the ring is
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An electron moves along the line AB, which lies in the same plane as a circular loop of conducting wires as shown in the diagram. What will be the direction of current induced if any, in the loop
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In the circuit shown switch k2 is open and switch k1 is closed at t = 0. At time t = to switch k1 is opened and switch k2 is simultaneously closed. The variation of inductor current with time is
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An equilateral triangular loop having a resistance R and length of each side l is placed in a magnetic field which is varying at 
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The area of the triangle formed by tangents drawn from the point (x1, y1) to the parabola y2 = 8x and its chord of contact is
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A uniform but time varying magnetic field is present in a circular region of radius R. The magnetic field is perpendicular and into the plane of the loop and the magnitude of the field is increasing at a constant rate 
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physics-General
