Magnetic effect of current practice · Medium

A charged particle moves in a circular path in a uniform magnetic field. If its speed is reduced, then its time period will

The materials for the construction of electro magnets should have

An electron moving with velocity $2 \times 10^7 \mathrm{~m} / \mathrm{s}$, describes a circle in a magnetic field of strength $2 \times {10^{ - 2}}T.$ If $\frac{\mathrm{e}}{\mathrm{m}}$ of electron is $1.76 \times 10^{11} \mathrm{C} / \mathrm{kg}$.
Then the diameter of the circle will be

A solenoid of length 22.5 cm has a total of 900 turns and carries a current of 0.8 A. What is the magnetizing field H near the centre and far away from the end of the solenoid?

The magnetic field at the centre of a circular coil of radius $r$, due to current $I$ flowing through it, is $B$. The magnetic field at a point along the axis at a distance $\frac{r}{2}$ from the centre is:

Statement-1 : The sensitivity of a moving coil galvanometer is increased by placing a suitable magnetic material as a core inside the coil.

and
Statement-2 : Soft iron has a high magnetic permeability and cannot be easily magnetized or demagnetized.

A positively charged particle moves in a region having a uniform magnetic field and uniform electric field in same direction. At time $t=0$, the velocity of the particle is perpendicular to the field direction. The subsequent path of the particle will be

A solenoid having 2000 turns per meter has a core of area $4 \mathrm{~cm}^2$ and relative permeability 220. It carries a current of $5 \mathrm{~A}$. The which statement among the following is true?

A 0.1 m long conductor carrying a current of 50A is perpendicular to a magnetic field of 1.25 mT. The mechanical power to move the conductor with a speed of 1m/s is

Assertion: A current element is a source of magnetic field.
Reason: A moving charge is a source of magnetic field.

In the cyclotron, as radius of the circular path of the charged particle increases :
$(\omega=$ angular velocity, $v=$ linear velocity)

A coil carrying electric current is placed in
uniform magnetic field, then

A tangent galvanometer shows a deflection $45^\circ$ when $10\;mA$ current passes through it. If the horizontal component of the earth’s field is $3.6 \times {10^{ - 5}}T$  and radius of the coil is $10\;cm$. The number of turns in the coil is

A stray magnetic field does ‘NOT’ affect the
deflection of moving coil galvanometer because

A charged particle moves in a gravity free space without change in velocity. Which of the following is not possible in that space?

A wire is formed into a circle having a diameter of $10.0 \mathrm{~cm}$ and placed in a uniform magnetic field of $3.00 \mathrm{~mT}$. The wire carries a current of $5.00 \mathrm{~A}$. Find (a) the maximum torque on the wire, and (b) the range of potential energies of the wire-field system for different orientations of the circle.

If the number of turns per unit length of a coil of a solenoid is doubled, the self inductance of the solenoid will

If the angular momentum of an electron is $\vec J\;$ then the magnitude of the magnetic moment will be

Assertion: The ion cannot move with speed beyond a certain limit in a cyclotron.

Reason: As velocity increases time taken by ion increases.

Assertion (A): In M.C.G, the deflection '$\theta$' is directly proportional to the strength of the current.

Reason (R): In M.C.G., the the torque experienced by the loop is $\mathrm {BiAN}\cos\theta$

This question has Statement I and Statement II. Of the four choices given after the statements, choose the one that best describes the two statements.

Statement I Higher the range, greater is the resistance of ammeter.

Statement II To increase the range of ammeter, additional shunt needs to be used across it.

The force experienced by a charge $q$ having velocity $v$ parallel to a magnetic field $B$ which acts on the charge

Statement-1: Two long parallel conductors carrying currents in the same direction experience a force of attraction.
Statement-2: The magnetic produced in the space between the conductors are in the same direction.

The current that must flow through the coil of a galvanometer so as to produce a deflection of one division on its scale is called

Assertion: A current carrying toroid is freely suspended in uniform magnetic field then torque acts on it is always zero.
Reason: The magnetic moment of current carrying toroid is zero.

A current carrying straight wire is kept along
the axis of a circular loop carrying a current.
The straight wire

A long solenoid of length $40 \mathrm{~cm}$ having 240 turns carries a current of $5 \mathrm{~A}$. The magnetic field at the centre of the solenoid is

If a velocity has both perpendicular and
parallel components while moving through a
magnetic field, what is the path followed by a
charged particle ?

A battery of emf $12 \mathrm{~V}$ and internal resistance $1.2 \Omega$ supplies a current through a coil of resistance $48 \Omega$. A voltmeter of resistance $72 \Omega$ is used to measure the potential difference across the coil. What would be the reading on the voltmeter ?

A moving coil galvanometer has $N$ number of turns in a coil of effective area $A$, it carries a current $I$. The magnetic field $B$ is radial. The torque acting on the coil is