Advertisements
Advertisements
प्रश्न
A circular coil expands radially in a region of magnetic field and no electromotive force is produced in the coil. This can be because ______.
- the magnetic field is constant.
- the magnetic field is in the same plane as the circular coil and it may or may not vary.
- the magnetic field has a perpendicular (to the plane of the coil) component whose magnitude is decreasing suitably.
- there is a constant magnetic field in the perpendicular (to the plane of the coil) direction.
विकल्प
a and b
b and c
c and d
a and d
Advertisements
उत्तर
b and c
Explanation:
As we know whenever the number of magnetic lines of force (magnetic flux) passing through a circuit changes an emf is produced in the circuit called induced emf. The induced emf persists only as long as there is a change or cutting of flux.
The induced emf is given by rate of change of magnetic flux linked with the circuit, i.e., `e = (-dphi)/(dt)`
According to the problem, there is no electromotive force produced in the coil. Then the various arrangement are to be thought of in such a way that the magnetic flux linked with the coil does not change even if the coil is placed and expanded in magnetic field.
When circular coil expands radially in a region of magnetic field such that the magnetic field is in the same plane as the circular coil or we can say that direction of magnetic field is perpendicular to the direction of area (increasing) so that their dot product is always zero and hence change in magnetic flux is also zero.
Or
The magnetic field has a perpendicular (to the plane of the coil) component whose magnitude is decreasing suitably in such a way that the dot product of magnetic field and surface area of plane of coil remain constant at every instant.
APPEARS IN
संबंधित प्रश्न
A 20 cm long conducting rod is set into pure translation with a uniform velocity of 10 cm s−1 perpendicular to its length. A uniform magnetic field of magnitude 0.10 T exists in a direction perpendicular to the plane of motion. (a) Find the average magnetic force on the free electrons of the rod. (b) For what electric field inside the rod, the electric force on a free elctron will balance the magnetic force? How is this electric field created? (c) Find the motional emf between the ends of the rod.
Consider the situation shown in the figure. Suppose the wire connecting O and C has zero resistance but the circular loop has a resistance Runiformly distributed along its length. The rod OA is made to rotate with a uniform angular speed ω as shown in the figure. Find the current in the rod when ∠ AOC = 90°.
Mechanical force per unit area of a charged conductor is ______
A conducting square loop of side l and resistance R moves in its plane with a uniform velocity v perpendicular to one of its side. A magnetic induction B constant in time and space, pointing perpendicular and into the plane of the loop exists everywhere. The current induced in the loop is ______.
The emf induced across the ends of a conductor due to its motion in a magnetic field is called motional emf. It is produced due to magnetic Lorentz force acting on the free electrons of the conductor. For a circuit shown in the figure, if a conductor of length l moves with velocity v in a magnetic field B perpendicular to both its length and the direction of the magnetic field, then all the induced parameters are possible in the circuit.
A 0.1 m long conductor carrying a current of 50 A is held perpendicular to a magnetic field of 1.25 mT. The mechanical power required to move the conductor with a speed of 1 ms-1 is ______.
Motional e.m.f is the induced e.m.f. ______
A magnetic field B = Bo sin ( ωt )`hatk` wire AB slides smoothly over two parallel conductors separated by a distance d (Figure). The wires are in the x-y plane. The wire AB (of length d) has resistance R and the parallel wires have negligible resistance. If AB is moving with velocity v, what is the current in the circuit. What is the force needed to keep the wire moving at constant velocity?
A wire of length 1 m moving with velocity 8 m/s at right angles to a magnetic field of 2 T. The magnitude of induced emf, between the ends of wire will be ______.
Figure shows a rectangular frame situated in a constant magnetic field. A wire BC of length 1 m is moved out with velocity 4 m/s. Magnetic field strength is 0.15 T. Force acting on the wire BC is:
In \[e=Blv\], what does \[l\] represent?
In \[e=Blv\], what does \[v\] represent?
What component must the conductor's velocity have for motional EMF?
What happens to motional EMF if \[\vec{v}\parallel\vec{B}\]?
What happens to motional EMF if \[\vec{v}\parallel\vec{l}\]?
Which orientation gives maximum motional EMF?
What is the motional EMF across a small element \[dr\] of a rotating rod?
