A straight current-carrying wire is placed along the axis of a current-carrying loop, then force between them is

An $\alpha -particle$completes 40,000 revolutions in a cyclotron before exiting from it. If potential difference between the Dees is 5000 V, then the energy gained by the particle is

Two wires of large length carry equal currents each i. One wire is kept along x-axis and the other is kept along y-axis. The magnitude of magnetic field at a point on z-axis at distance d from the origin is

To compensate the relativistic variation of mass at high speed of charge in cyclotron. Adjustments can be made is :

A infinite straight wire carrying current 3 A and other carrying 6 A in the same direction produce a magnetic field of 12 tesla at the midpoint of the line joining them. When 6-ampere current wire is switched off, the magnetic field will be :

The magnetic field at origin in the situation shown in the figure has magnitude (BCD is a semi-circular arc of radius R in xz plane) 

Three long straight wires A, B, and C are shown in figure. The resultant magnetic force on wire B is 

In a moving coil galvanometer the deflection $\theta$ of the coil is related to the electric current by the relation

A half-metre long wire is lying in a plane perpendicular to the magnetic field. A force of 2 kg wt is acting on it in a magnetic field of 0.98 tesla. The current flowing in it will be

A cyclotron cannot be used to accelerate 

A conductor AB of length l, carrying a current $i_2$, is placed antiparallel to a long straight conductor XY carrying a current $i_1$ as shown. The force on AB has magnitude-

Two long straight conductors with currents $l_1 and l_2$ are placed along X and Y-axes. The locus of points of zero magnetic induction is

Cyclotron frequency does not depend upon

The maximum kinetic energy of an $\alpha -particle$ coming out of a cyclotron accelerator is 20 MeV. The maximum kinetic energy of a proton that can be obtained from this accelerator is 

In a moving coil galvanometer, magnetic fields line by magnet are made

A wire abcdef with each side of length L bent as shown and carrying a current I is placed in a uniform magnetic field B parallel to the positive y-direction. What is the magnitude and direction of the force experienced by the wire?

Current sensitivity of a moving coil galvanometer is 1 rad $A^{-1}$ and its resistance is $5\Omega$. Its voltage sensitivity is

Torque on a current-carrying coil is maximum in a uniform magnetic field, when

In which of the following situations will there be no force?

A straight wire of length ${\left(\mathrm{\pi }\right)}^2$ metre is carrying a current of 2 A and the magnetic field due to it is measured at a point distance 1 cm from it. If the wire is to be bent into a circle and is to carry the same current as before, the ratio of the magnetic field at its center to that obtained in the first case would be

A current-carrying wire is placed in non-conducting liquid medium of refractive index n and relative electrical permittivity ${\epsilon }_r$. Then magnetic field at a point r distance of the point from the element is given by

Magnetic field due to straight current-carrying conductor is 

The Ampere law is based on which theorem?

To which law of electricity is Biot Savart law of magnetism analogous to

A: A magnetic dipole may have non-zero torque and zero force in the non-uniform magnetic field.

R: In a uniform magnetic field, the net force on the magnetic dipole is always zero and torque may not be zero.

A long solenoid of 50 cm length having 100 turns carries a current of 2.5 A. The magnetic field at the centre of the solenoid is:

$\left({\mathrm{\mu }}_0=4\mathrm{\pi }\times {10}^{-7} \mathrm{T} \mathrm{m} {\mathrm{A}}^{-1}\right)$

In a chamber, a uniform magnetic field of 6.5 G (1 G = 10^–4 T) is maintained. An electron is shot into the field with a speed of 4.8 ×${10}^6$ m s^–1 normal to the field. the radius of the circular orbit is:
(e = 1.6 × 10^–19 C, $m_e$ = 9.1×10^–31 kg)

$$\begin{gathered} \left(1\right) 4.2 cm \\ \left(2\right) 5.3 cm \\ \left(3\right) 4.7 cm \\ \left(4\right) 5.2 cm \end{gathered}$$

A circular coil of 30 turns and a radius of 8.0 cm carrying a current of 6.0 A is suspended vertically in a uniform horizontal magnetic field of magnitude 1.0 T. The field lines make an angle of 60° with the normal of the coil. What will be the magnitude of the counter-torque that must be applied to prevent the coil from turning?

Two concentric circular coils X and Y of radii 16 cm and 10 cm, respectively, lie in the same vertical plane containing the north to south direction. Coil X has 20 turns and carries a current of 16 A, coil Y has 25 turns and carries a current of 18 A. The sense of the current in X is anticlockwise, and clockwise in Y, for an observer looking at the coils facing west. The magnitude and direction of the net magnetic field due to the coils at their centre is:

$$\begin{gathered} \left(1\right) 2\pi \times {10}^{-4} T \left(East\right) \\ \left(2\right) 5\pi \times {10}^{-4} T \left(East\right) \\ \left(3\right) 5\pi \times {10}^{-4} T \left(West\right) \\ \left(4\right) 4\pi \times {10}^{-4} T \left(West\right) \end{gathered}$$

A straight horizontal conducting rod of length 0.45 m and mass 60 g is suspended by two vertical wires at its ends. A current of 5.0 A is set up in the rod through the wires. (a) What magnetic field should be set up normally to the conductor in order that the tension in the wires is zero?