Advertisements
Advertisements
प्रश्न
Consider a long, straight wire of cross-sectional area A carrying a current i. Let there be n free electrons per unit volume. An observer places himself on a trolley moving in the direction opposite to the current with a speed \[v = \frac{i}{\text{nAe}}\] and separation from the wire by a distance r. The magnetic field seen by the observer is very nearly
पर्याय
- \[\frac{\mu_0 i}{2\pi r}\]
zero
- \[\frac{\mu_0 i}{\pi r}\]
- \[\frac{2 \mu_0 i}{\pi r}\]
Advertisements
उत्तर
B = \[\frac{\mu_o i}{2\pi r}\]
APPEARS IN
संबंधित प्रश्न
A point charge q moving with speed v enters a uniform magnetic field B that is acting into the plane of the paper as shown. What is the path followed by the charge q and in which plane does it move?
Sketch a schematic diagram depicting oscillating electric and magnetic fields of an em wave propagating along + z-direction ?
The motion of copper plate is damped when it is allowed to oscillate between the two poles of a magnet. What is the cause of this damping?
A moving charge produces
Consider the situation shown in figure. The wire PQ has mass m, resistance r and can slide on the smooth, horizontal parallel rails separated by a distance l. The resistance of the rails is negligible. A uniform magnetic field B exists in the rectangular region and a resistance R connects the rails outside the field region. At t = 0, the wire PQ is pushed towards right with a speed v0. Find (a) the current in the loop at an instant when the speed of the wire PQ is v, (b) the acceleration of the wire at this instant, (c) the velocity vas a functions of x and (d) the maximum distance the wire will move.
Consider the situation shown in figure. The wires P1Q1 and P2Q2 are made to slide on the rails with the same speed 5 cm s−1. Suppose the 19 Ω resistor is disconnected. Find the current through P2Q2 if (a) both the wires move towards right and (b) if P1Q1 moves towards left but P2Q2 moves towards right.
A magnetic field that varies in magnitude from point to point but has a constant direction (east to west) is set up in a chamber. A charged particle enters the chamber and travels undeflected along a straight path with constant speed. What can you say about the initial velocity of the particle?
A charged particle moves through a magnetic field perpendicular to its direction. Then ______.
-
The presence of a large magnetic flux through a coil maintains a current in the coil if the circuit is continuous.
-
A coil of a metal wire kept stationary in a non– uniform magnetic field has an e.m.f induced in it.
-
A charged particle enters a region of uniform magnetic field at an angle of 85° to the magnetic lines of force, the path of the particle is a circle.
-
There is no change in the energy of a charged particle moving in a magnetic field although a magnetic force is acting on it.
A moving charge will gain kinetic energy due to the application of ______.
A circular coil of radius 10 cm is placed in a uniform magnetic field of 3.0 × 10-5 T with its plane perpendicular to the field initially. It is rotated at constant angular speed about an axis along the diameter of coil and perpendicular to magnetic field so that it undergoes half of rotation in 0.2 s. The maximum value of EMF induced (in µV) in the coil will be close to the integer ______.
A thin strip 10 cm long is on a U-shaped wire of negligible resistance and it is connected to a spring of spring constant 0.5 Nm-1. The assembly is kept in a uniform magnetic field of 0.1 T. If the strip is pulled from its equilibrium position and released, the number of oscillations it performs before its amplitude decreases by a factor of e is N. If the mass of the strip is 50 grams, its resistance is 10 Ω, and air drag is negligible, N will be close to ______.
A square coil ABCD with its plane vertical is released from rest in a horizontal uniform magnetic field `vec"B"` of length 2L. The acceleration of the coil is ______.
A conductor ABOCD moves along its bisector with a velocity 1 m/s through a perpendicular magnetic field of 1 wb/m2, as shown in figure. If all the four sides are 1 m length each, then the induced emf between A and Din approx is ______V.
Protons and singly ionized atoms of U235 and U238 are passed in turn (which means one after the other and not at the same time) through a velocity selector and then enter a uniform magnetic field. The protons describe semicircles of radius 10 mm. The separation between the ions of U235 and U238 after describing the semicircle is given by ______.
A charged particle of charge q and mass m is projected in a region that contains an electric and magnetic field as shown in the figure with velocity V at an angle of 45° with x-direction. If V = `sqrt((qE)/m)`, then net deviation in particle motion will be (neglect the effect of gravity) in a clockwise direction approx ______ °.
An electron (mass 9 × 10−31 kg and charge 1.6 × 10−19 C) moving with speed c/100 (c = speed of light)is injected into a magnetic field `vecB` of magnitude 9 × 10−4 T perpendicular to its direction of motion. We wish to apply an uniform electric field `vecE` together with the magnetic field so that the electron does not deflect from its path. Then (speed of light c = 3 × 108 m s−1).
