Magnetic effect of current practice · Mixed difficulty

Assertion: Magnetic force between two charges is generally much smaller than the electric force between them.
Reason: Speeds of charges are much smaller than the free–space speed of light.

In which of the following case no force exerted
by a magnetic field on a charge ?

A proton enters into a magnetic field of induction $1.732 \mathrm{~T}$, with a velocity of $10^7 \mathrm{~m} / \mathrm{s}$ at an angle $60^{\circ}$ to the field. The force acting on the proton is $\left(\mathrm{e}=1.6 \times 10^{-19} \mathrm{C}, \sin 60^{\circ}=\cos 30^{\circ}=\right.$ $\frac{\sqrt{3}}{2}$ )

A long straight wire carries a current $15 \mathrm{~A}$. Calculate the magnetising field $\mathrm{H}$ at a point at distance $0.105 \mathrm{~m}$ from the axis of wire

A solenoid of 1000 turns per meter has a core with relative permeability 500. Insulated windings of the solenoid carry an electric current of 5A. The magnetic flux density produced by the solenoid is (permeability of free space $= \,\,4\pi \times {10^{ - 7}}\mathrm{H/m}$ )

A circular coil carrying a certain current produces a magnetic field $B_0$ at its centre. The coil is now rewound so as to have 4 turns and the same current is passed through it. The new magnetic field at the centre is

Statement-I: If by mistake a voltmeter is connected in series it gets burnt
Statement-II: Current will drastically decrease in the circuit.

The turns of a solenoid, designed to provide a given magnetic
flux density along its axis, are wound to fill the space between
two concentric cylinders of fixed radii. How should the diameter
$d$ of the wire used be chosen so as to minimize the heat
dissipated in the windings?

Fleming's left and right hand rules are used in:

The ratio of time periods of $\alpha$-particle and proton moving on circular path in uniform transverse magnetic field :-

The magnetic induction at the centre of a current carrying circle of radius $r$, is

A charge of $3.14 \times 10^{-6} \mathrm{C}$ is distributed uniformly over a circular ring of radius $20.0 \mathrm{~cm}$. The ring rotates about its axis with an angular velocity of $60.0\, \mathrm{rad}\, \mathrm{s}^{-1}$. Find the ratio of the electric field to the magnetic field at a point on the axis at a distance of $5.00 \mathrm{~cm}$ from the centre.

Two parallel wires are carrying electric currents of equal magnitude and in the same direction. They exert:

A solenoid $60 \mathrm{~cm}$ long and of radius $4.0 \mathrm{~cm}$ has 3 layers of windings of 300 turns each. A $2.0 \mathrm{~cm}$ long wire of mass $2.5 \mathrm{~g}$ lies inside the solenoid near its centre normal to its axis; both the wire and the axis of the solenoid are in the horizontal plane. The wire is connected through two leads parallel to the axis of the solenoid to an external battery which supplies a current of $6.0 \mathrm{~A}$ in the wire. What value of current in the windings of the solenoid can support the weight of the wire ? $g=9.8 \mathrm{~ms}^{-2}$.

An ideal coil of 10 henry is joined in series with a resistance of $5 \mathrm{ohm}$ and a battery of 5 volt. After two seconds joining, the current flowing in ampere in the circuit will be :-

An electron having charge ' $e$ ' is moving with a constant speed $v$ along a circle of radius $r$. Its magnetic moment will be

A 0.8 m long solenoid has 800 turns and has a field density of $2.52\mathrm{ } \times \mathrm{ }{10^{ - 3}}T$ at its centre. What is current in the wire ?

A galvanometer of resistance $25\,\,\mathrm{\Omega }$ giving full scale deflection for a current of $10\,\,milli\,\,ampere$, is to be changed into a voltmeter of range $100\,\,V$ by connecting a resistance of $'R'$ in series with galvanometer. The value of resistance $R$ in $\mathrm{\Omega }$ is

A galvanometer has resistance 500 ohm. It is shunted so that its sensitivity decreases by 100 times. Find the shunt resistance.

Two long straight conductors carry currents $3 A$ and $1 A$ into the plane of paper. A circular path is imagined to enclose these currents. The value of $\oint \vec{B} \cdot \overrightarrow{d l}$ is

A galvanometer with a coil resistance of $100\,\,\Omega$ gives a full-scale deflection when a current of $1\,\,mA$ is passed through it. The resistance of the shunt needed in ohm to convert this galvanometer into an ammeter of range $10\,A$ is nearly.

When a charged particle enters a uniform magnetic field

Armature current is maximum in a DC motor when the motor has

A galvanometer of resistance $\mathrm{20}\,\,\mathrm{\Omega }$ shows a deflection of $\mathrm{10}$ divisions when a current of $\mathrm{1}\,\,\mathrm{mA}$ is passed through it. If a shunt of $\mathrm{4}\,\,\mathrm{\Omega }$ is connected and there are $\mathrm{50}$ divisions on the scale, the range of the galvanometer is

A charged particle enters in a uniform
magnetic field with a certain velocity. The
power delivered to the particle by the magnetic
field depends on

Assertion : In electric circuits, wires carrying
currents in opposite directions are often twisted
together.
Reason: If the wires are not twisted together, the
combination of the wires forms a current loop, the
magnetic field generated by the loop might affect
adjacent circuits or components

An alternating electric field, of frequency $v$, is applied across the dees (radius $=R$) of a cyclotron that is being used to accelerate protons (mass = $m$). The operating magnetic field $(B)$ used in the cyclotron and the kinetic energy ($K$) of the proton beam, produced by it, are given by

Maximum kinetic energy gained by the
charged particle in the cyclotron in
independent of

The work done by an uniform magnetic field, on a moving charge is

A straight long conductor carries current along the positive $x$-axis. Identify the correct statement related to the four points $A(a, a, 0), B(a, 0, a), C(a,-a, 0)$ and $D(a, 0,-a)$.