Magnetic effect of current practice · Medium

If the maximum value of accelerating potentia provided by a radio frequency oscillator be $20\,\mathrm{kV}$, find the number of revolutions made by a proton in a cyclotron ts achieve one fifth of the speed of light. Mass of a proton $=1.67 \times 10^{-27} \mathrm{~kg}$.

A particle of mass $m$ and charge $q$ enters a magnetic field $B$ perpendicularly with a velocity $v$. The radius of the circular path described by it will be

An arbitrary shaped closed coil is made of a
wire of length L and a current I ampere is
flowing through it. The plane of the coil is
perpendicular to magnetic field B, the force on
the coil is

Assertion (A) : A charged particle enters in a magnetic field $\mathbf{B}=B_0 \hat{\mathbf{i}}$ with velocity $\mathbf{v}=v_0 \hat{\mathbf{i}}+v_0 \hat{\mathbf{j}}$, then minimum speed of charged particle may be $v_0$.

Reason (R) : A variable acceleration will act on the charged particle.

A charged particle is projected in to a region where there may have an electric filed $\vec{E}$ and/or magnetic field $\bar{B}$. If the charged particle goes un-accelerated, then it is not possible that

‘Biot-Savarts’ law of magnetism is analogous
to:

A proton enters a magnetic field with velocity
parallel to the magnetic field. The path
followed by the proton is a

A charge $q$ moves with velocity $\vec{v}$ in the direction of the applied field $\vec{B}$. The force that acts on the charge is

An electron and a proton, both having the same kinetic energy, enter a region of uniform magnetic field, in a plane perpendicular to the field. If their masses are denoted by $m_e$ and $m_p$ respectively, then the ratio of the radii (electron to proton) of their circular orbits is

A galvanometer coil is replaced by another coil of diameter one-fourth of the original diameter and the total number of turns as ten times the original number. What will be the new deflection if the same current is passed through it? Old deflection is $\theta$.

Assertion (A): Magnetic field interacts with a moving charge and not with a stationary charge.

Reason (R): Magnetic field will be produced by a moving charge but not by a stationary charge.

A charge $q$ is moving with a velocity $v$ parallel to a magnetic field $B$. Force on the charge due to magnetic field is

A current carrying coil is subjected to a
uniform magnetic field. The coil will orient so
that its plane becomes

A short bar magnet is placed with its axis at $30^{\circ}$ with an external field $0.05 \mathrm{~T}$. If the magnetic moment of the magnet is $0.8 \mathrm{Am}^2$, then the torque experienced by the magnet is

A solenoid of length $0.5 \mathrm{~m}$ has a radius of $1 \mathrm{~cm}$ and is made up of 500 turns. It carries a current of $5 \mathrm{~A}$. What is the magnitude of the magnetic field inside the solenoid?

The gyromagnetic ratio of an electron $=$ $\_\_\_\_$ specific charge of an electron.

A long solenoid is formed by winding 20 turns/cm. The current necessary to produce a magnetic field of 20 millitesla inside the solenoid will be approximately

$\left(\frac{\mu_0}{4 \pi}=10^{-7} \text { tesla }- \text { metre } / \text { ampere }\right)$

In a cyclotron, a charged particle

A current of $i$ ampere flows along an infinitely long straight thin walled tube, then the magnetic induction at any point inside the tube is

Assertion: A planar circular loop of area $A$ and current $I$ is equivalent to magnetic dipole of dipole moment $M = IA.$
Reason: At large distances, magnetic field of circular loop and magnetic dipole is same.

A current carrying small loop behaves like a small magnet. If $A$ be its area and $M$ its magnetic moment, the current in the loop will be

If an ammeter is to be used in place of a voltmeter, then we must connect with the ammeter a

An electron having mass $9 \times {10^{ - 31}}\,kg$, charge $1.6 \times {10^{ - 19}}C$ and moving with a velocity of ${10^6}\,m/s$ enters a region where magnetic field exists. It is describes a circle of radius 0.10 m, the intensity of magnetic field must be [in Tesla]

Magnetic field at any point on the axis of a current element is

Similar or same magnetic fields can be
produced by

If we double the radius of a coil keeping the current through it unchanged, then the magnetic field at any point at a large distance from the centre becomes approximately

The current sensitivity of a moving coil galvanometer depends on

A particle of mass $m$, charge $Q$ and kinetic energy is $10 \mathrm{~J}$ enters a transverse uniform magnetic field $\vec{B}$. After 5 seconds the kinetic energy of the particle will be :-

Proton (charge $+\mathrm{e}$, mass $\mathrm{m}$ ) are being accelerated in a cyclotron where a magnetic field $\vec{B}$ is applied perpendicular to the dees and a battery of $V$ volts in connected across the dees to accelerate the protons. The number of revolutions per second (frequency in $\mathrm{Hz}$ ) by the protons is

A current carrying loop of radius $r$ carries a current $I$ in clock wise direction. It is placed in a uniform magnetic field $B$ such that plane of the coil is parallel to field. The net torque on the coil is