Magnetic effect of current practice · Medium

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 $D(a, 0,-a)$.

When the number of turns of the coil is
doubled, the current sensitivity of a moving coil
galvanometer is doubled whereas the voltage
sensitivity of the galvanometer

A charged dust particle of radius $5 \times {10^{ - 7}}$m is located in a horizontal electric field having an intensity of $6.28 \times {10^5}\;\mathrm{V}{\mathrm{m}^{ - 1}}$. The surrounding medium in air with coefficient of viscosity $\mathrm{\eta } = 1.6 \times {10^{ - 15}}\mathrm{Ns}{\mathrm{m}^{ - 2}}.$ If this particle moves with a uniform horizontal speed of 0.01 $\mathrm{m}{\mathrm{s}^{ - 1}},$ the number of electrons on it will be

A non-planar closed loop of arbitrary shape carrying a current $I$ is placed in uniform magnetic field. The force acting on the loop

When a charged particle moves perpendicular
to a uniform magnetic field, there is a change in
its:

Statement (A): The restoring couple in the moving coil galvanometer is due to the current in the coil

Statement(B): Wires of magnetic field around a current carrying straight conductor will be circular in a plane parallel to the conductor

Statement(C): When a charged particle enters a uniform magnetic field, its kinetic energy increases

The direction of the force on a current carrying
conductor held perpendicular to a uniform
magnetic field is given by

A galvanometer can be converted into a voltmeter by connecting

Assertion: A linear solenoid carrying current is equivalent to a bar magnet.
Reason: The magnetic field lines due to current carrying solenoid resemble exactly with those of a bar magnet.

In a moving coil galvanometer, to make the
field radial

A solenoid consists of 100 turns of wire and has a length of 10 cm. The magnetic field inside the solenoid when it carries a current of 0.500 A will be

In moving coil galvanometer, strong horse shoe
magnet of concave shaped pole pieces is used to

The two parallel wires carry current in
opposite directions

If an electron of velocity $(2\hat{i} +3\hat{j})$ is subjected to magnetic field of $4\hat{k} ,$ then its

(a) path will change

(b) speed does not change

(c) path must be circular

(d) momentum is constant

A bar magnet is placed inside a uniform
magnetic field. What does it experience?

A closely wound solenoid of length $1 \mathrm{~m}$ has 5 layers of 500 turns each. If the magnitude of magnetic field inside the solenoid near its centre is $4.4 \mathrm{mT}$, the current carried is-

Current $\mathrm{i}$ is carried in a wire of length $\mathrm{L}$. If the wire is turned into a circular coil, the maximum magnitude of torque in a given magnetic field $\mathrm{B}$ will be:

An electron is moving in a circle of radius $r$ in a uniform magnetic field B. Suddenly, the field is reduced to $\frac{B}{2}$. The radius of the circular path now becomes :

Two solenoids are given- 1 st has 1 turn per unit length and 2nd has $n$ turns per unit length. Ratio of magnetic fields at their centers is

Assertion (A): The coil is bound over the metallic frame in moving coil galvanometer.
Reason (R): The metallic frame helps in making steady deflection without any oscillations.