Magnetic effect of current practice · Medium

Two straight parallel wires carry currents of $200\,\,{\mkern 1mu} mA\,\,{\mkern 1mu} \mathrm{and}\,\,\,{\mkern 1mu} 1A$ in opposite directions. If the wires are 20 cm apart, the distance of the neutral point from the $1A$ wire is (in cm)

A long cylindrical wire kept along ${Z}$-axis carries a current of density $\bar{J}=J_0 r \hat{k}$ where $J_0$ is a constant and ${r}$ is the radial distance from the axis of the cylinder. The magnetic induction ${B}$ inside the conductor at a distance ${d}$ from the axis of the cylinder is

A solenoid, of length $1.5 \mathrm{~m}$, has a radius of $1.5 \mathrm{~cm}$ and has a total of 1500 turns wound on it. It carries a current of $3 \mathrm{~A}$. Calculate the magnitude of the axial magnetic field inside the solenoid. If an electron were to move with a speed of $2 \times 10^4 \mathrm{~ms}^{-1}$ along the axis of this current carrying solenoid, what would be the force experienced by this electron?

Given the fact that
A) Magnetic field exerts force only on a moving
charge
B) Electric field exerts force on both stationary
and moving charge
C) Magnetic field exerts force on charge moving
parallel to the direction of the field.
Which of the following is true?

Given below are two statements:

Statement I: If the number of turns in the coil of a moving coil galvanometer is doubled then the current sensitivity becomes double.

Statement II: Increasing current sensitivity of a moving coil galvanometer by only increasing the number of turns in the coil will also increase its voltage sensitivity in the same ratio

In the light of the above statements, choose the correct answer from the options given below:

A charged particle moving in a magnetic field
is increased in its velocity, then its radius of the
circle

Statement-1: Net force on a current carrying loop in a non-uniform magnetic field must be non-zero.
Statement-2: Force on a current carrying wire of length $\vec{dl}$ placed in magnetic field $\overrightarrow{{B}}$ is given by $\overrightarrow{d {F}}=i \vec{dl} \times \overrightarrow{{B}}$

A particle of charge $q$ moves in a circle of radius $r$ with speed $v$. Treating the circular path as a current loop with an average current, find the maximum torque exerted on the loop by a uniform field of magnitude $B$.

Magnetic fields at two points on the axis of a circular coil at a distance of 0.05m and 0.2m from the centre are in the ratio 8 : 1. The radius of coil is

A long straight solenoid with cross sectional radius ' $a$ ' and number of turns per unit length ' $n$ ' has a current varying width time as $I\left(\mathrm{As}^{-1}\right)$. The magnitude of the electric field as a function of distance ' $r$ ' from the solenoid axis is

A cyclotron is used to accelerate :

A current carrying circular coil, suspended
freely in a uniform external magnetic field
orients to a position of stable equilibrium. In
this state:

A wire of length $2 \mathrm{~m}$ carrying a current of $1 \mathrm{~A}$ is bent to form a circle, the magnetic moment of the coil is

For a long current carrying solenoid having inside magnetic field is $0.6 \mathrm{~T}$. Then find the magnetic energy per unit volume is

Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason
R.
Assertion A: For measuring the potential difference across a resistance of $600 \,\Omega$, the
voltmeter with resistance $1000 \,\Omega$ will be preferred over voltmeter with resistance $4000\,\Omega.$
Reason R: Voltmeter with higher resistance will draw smaller current than voltmeter with lower resistance.
In the light of the above statements, choose the most appropriate answer from the options given below:

An electron is moving with velocity $10^7 \mathrm{~m} / \mathrm{s}$ on a circular path of radius $0.57 \mathrm{~cm}$ in a magnetic field of $10^{-2} \mathrm{~Wb} / \mathrm{m}^2$. Find the value of e/m for electron in $\text { coulomb } / \mathrm{kg}$.

A $+6 \mu \mathrm{C}$ point charge is moving at a constant velocity of $8 \times 10^6 \mathrm{~ms}^{-1}$ in the $+y$ direction, relative to a reference frame. At the instant when the point charge is at the origin of this reference frame, what is the magnetic field vector it produces at the following points?
(a) $x=0.500 \mathrm{~m}, y=0, z=0$, and
(b) $x=0, y=-0.500 \mathrm{~m}, z=0$.

Consider a wire carrying a steady current, $i$ placed in a uniform magnetic field ${B}$ perpendicular to its length. Consider the charges inside the wire. It is known that magnetic forces do no work. This implies that,

Inside a cyclotron, a charged particle is
subjected to both an electric field and a
magnetic field. It gains kinetic energy due to

A straight wire of diameter $0.5 \mathrm{~mm}$ carrying a current of $1 \mathrm{~A}$ is replaced by another wire of $1 \mathrm{~mm}$ diameter carrying the same current. The strength of the magnetic field far away is

A proton is projected with a uniform velocity v along the axis of a current - carrying solenoid, then :

A horizontal wire, of length $5 \mathrm{~cm}$ and carrying a current of $2\mathrm{A}$ placed in the middle of a long solenoid and right angles to its axis. The solenoid has 1000 turns per metre and carries a steady current I. Calculate I if the force on the wire is vertically downwards and equal to $10^{-4} \mathrm{~N}$.

A circuit to verify Ohm’s law uses ammeter and voltmeter in series or parallel connected correctly to the resistor. In the circuit

The relation between voltage sensitivity $({\sigma _V})$ and current sensitivity $\left( {{\sigma _i}} \right)$ of a moving coil galvanometer is (resistance of galvanometer is G).

A circular loop of radius 0.0157 m carries a current of 2 Amperes. The magnetic field at the centre of the loop is $\left[ {{\mu _ \circ } = 4\pi \times {{10}^{ - 7}}\,\,wb/A - m} \right]\,\left[ {in\,\,wb/{m^2}} \right]$

A long solenoid with 2000 turns per meter has a small loop of radius $3 \mathrm{~cm}$ placed inside the solenoid normal to its axis. If the current through the solenoid increases steadily from 1.5 A to $5.5 \mathrm{~A}$ in $\frac{\pi^2}{100} \mathrm{~s}$, the induced emf in the loop is

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

Statement-A: When a charge particle of charge '$q$' moves with a velocity $v$ in magnetic field of induction $\vec{B}$ then force acting on it $\vec{F}=q(\vec{V} \times \vec{B})$

Statement-B: An electron is projected in a magnetic field along the lines of force then their will be no effect on the motion of electron.

A wire $28 \mathrm{~m}$ long is bent into $N$ turns of circular coil of diameter $14 \mathrm{~cm}$ forming a solenoid of length $60 \mathrm{~cm}$. Calculate the flux density inside it when a current of $5\,\mathrm{amp}$ passed through it. $\left(\mu_0=12.57 \times 10^{-7} \mathrm{~m}^{-1}\right)$

An electron of mass $9 \times 10^{-31} \mathrm{~kg}$ and charge 1.6 $\times 10^{-19} \mathrm{C}$ moving with a velocity of $10^6 \mathrm{~ms}^{-1}$ entered a magnetic field normally and described a circle of radius $10 \mathrm{~cm}$. Then the intensity of the magnetic field is