Question 1 :
A solenoid of n turns carries current I while another solenoid of same length and of $3$ n turns carries current $4I.$ What is the ratio of the magnetic strengths of the two solenoid ?
Question 2 :
The magnetic induction at a point at a large distance d on the axial line of circular coil of small radius carrying current is 120 $\mu T$. At a distance 2d the magnetic induction would be:<br/>
Question 3 :
A charged particle is moving on circular  path with velocity v in a uniform magnetic field B, if the velocity of the charged particle is doubled and strength of magnetic field is halved, then radius becomes :
Question 4 :
There will be no force between two wires carrying currents if currents are
Question 5 :
An electron moves at right angle to a magnetic field of $15\times { 10 }^{ -2 }T$ with a speed of $6\times { 10 }^{ 7 }{ m }/{ s }$. If the specific charge of the electron is $1.7\times { 10 }^{ 11 }{ C }/{ kg }$. The radius of the circular path will be
Question 6 :
A charged particle moving along positive x-direction with a velocity $v$ enters a region where there is a uniform magnetic field $\vec{B}=-B\hat{k}$,from x=0 to x=d.The particle gets deflected at an angle $\theta$ from its initial path.The specific charge of the particle is 
Question 7 :
One meter length of wire carries a constant current. The wire is bent to form a circular loop. The magnetic field at the center of this loop is $B$. The same is now bent to form a circular loop of smaller radius to have four turns in the loop. The magnetic field at the centre of this new loop is
Question 8 :
An electron of mass $m$ and charge $q$ is travelling with a speed $v$ along a circular path of radius $r$ at right angles to a uniform magnetic field $B$. If speed of the electron is doubled and the magnetic field is halved, then resulting path would have a radius of
Question 9 :
A bar magnet, held horizontally, is set into angular oscillations in the earth's magnetic field. Its time periods are $T_1$ and $T_2$ at two places where the angles of dip are $\theta_1$ and $\theta_2$ respectively. The ratio of the resultant magnetic fields at these two places will be:
Question 10 :
A stream of electrons is projected horizontally to the right. A straight conductor carrying a current is supported parallel to the electron stream and above it. If the current in the conductor is from left to right, what will be the effect on the electron stream?<br>
Question 11 :
A long wire carries a steady current. It is bent into a circle of one turn and the magnetic field at thecentre of the coil is $B.$ It is then bent into a circular loop of n turns. The magnetic field at the centreof the coil will be:
Question 12 :
Two long straight parallel wires separated by a distance, carrying equal currents exert a force F per unit length on each other. If the distance of separation is doubled, and the current in each is halved, the force per unit length, between them will be :<br/>
Question 13 :
If a charged particle goes unaccelerated in a region containing electric and magnetic fields,<br>
Question 14 :
Consider the following statements:<br>A) Time period of a charged particle in uniformmagnetic field is independent of K.E of the particle<br>B) Time period of a charged particle in uniformmagnetic field depends on the angle betweenvelocity and magnetic field<br>C) Time period of a charged particle in uniformmagnetic field is inversely proportional to specificcharge<br>
Question 15 :
Two long and parallel straight wires A and B are carrying currents of 4 A and 7 A in the same direction are separated by a distance of 5 cm. The  force acting on an 8 cm section of wire A is:
Question 16 :
A small current element of length $dl$ and carrying current is placed at $(1, 1, 0)$ and is carrying current in '$+z$' direction. If magnetic field at origin be $\overrightarrow{B}_1$ and at point $(2, 2, 0)$ be $\vec B_2$ then
Question 17 :
An electrically charged particle enters into a uniform magnetic induction field in a direction perpendicular to the field with a velocity $V$. Then, it travels:
Question 18 :
An electron of charge $e$ and mass $m$ describes a circular path of radius $r$ when it is projected with a velocity $v$ perpendicular to a uniform magnetic field, then its frequency is :<br/>
Question 19 :
Assertion: The energy of a charged particle moving in a uniform magnetic field does not change.
Reason: Work done by magnetic field on the charge is zero.
Question 20 :
Assertion: A loosely round helix made of stiff wire is suspended vertically with the lower end just touching a dish of mercury. When a current is passed through the wire, the helical wire executes oscillatory motion with the lower end jumping out of and inside of mercury.
Reason: When electric current is passed through helix, a magnetic field is produced both inside and outside the helix.
Question 21 :
A charged particle of mass $m$ and charge $q$ travels on a circular path of radius $r$ that is perpendicular to a magnetic field $B$. The time taken by the particle to complete one revolution is :
Question 22 :
When a galvanometer is shunted with a $4\Omega$ resistance, the deflection is reduced to one - fifth. If the galvanometer is further shunted with a $2\Omega$ wire, determine current in galvanometer now if initially current in galvanometer is $I_{0}$ (given main current remain same).
Question 23 :
A stream of electrons is projected horizontally to the right. A straight conductor carrying a current is supported parallel to the electron stream and above it. If the current in the conductor is from left to right, what will be the effect on the electron stream?<br>
Question 24 :
A current of i ampere is flowing in an equilateral triangle of side a. The magnetic induction at the centroid will be?
Question 25 :
<span class="wysiwyg-font-size-small"><span class="wysiwyg-font-size-small">Whichof the following particles will experience maximum magnetic force (magnitude) when projected with the same velocity perpendicular to a magnetic field?<br>
Question 26 :
A horizontal wire 0.1 m long carries a current of 5 A. Find the magnitude of the magnetic field, which can support the weight of the wire. Assume wire to be of mass $3 \times 10^{-3}kg  m^{-1}$ :<br/>
Question 27 :
A particle of mass m carrying charge $q$ is accelerated by a potential difference $V$. It enters perpendicularly in a region of uniform magnetic field $B$ and executes circular arc of radius $R$, then $q/m$ is equal to :<br/>
Question 28 :
In which of the following situations, the magnetic field can accelerate a charge particle at rest?<br>I. When the magnetic field is uniform with respect to time as well as position<br>II. When the magnetic field is time varying but uniform w.r.t position<br>III. When the magnetic field is time independent but position dependent.
Question 29 :
An electron accelerated through a potential difference $V$ passes through a uniform transverse magnetic field and experiences a force $F$. If the accelerating potential is increased to $2V$, the electron in the same magnetic field will experience a force :
Question 30 :
Find theratio of the conduction electronsto the total number of atoms in the given conductor.
Question 31 :
Consider the motion of a positive point charge in a region where are simultaneous uniform electric and magnetic field $\vec E=E_0\hat j$ and $\vec B=B_0\hat j$. At time $t=0$, this charge has velocity $\vec v$ in the x-y plane, making an angle $\theta$ with the x-axis. Which of the following option(s) is (are) correct for time $t > 0$?<br>
Question 32 :
A charged particle revolves in circular path in uniform magnetic field after accelerating by a potential difference of V volts.Choose the correct options if V is doubled.
Question 33 :
A very long solenoid has $800$ turns per metre length of the solenoid. A current of $1.6 A $ flows through it. Then the magnetic induction at the middle point of the solenoid on its axis is approximately.
Question 34 :
An ideal solenoid of cross-sectional area ${10}^{-4}{m}^{2}$ has $500$ turns per metre. At the centre of this solenoid, another coil of $100$ turns is wrapped closely around it, if the current in the coil charges from $0$ to $2\ A$ in $3.14\ ms$, the emf developed in the second coil is:
Question 35 :
A coil carrying current '$I$' has radius '$r$' and number of turns '$n$'. It is rewound so that radius of new coil is '$\dfrac{r}{4}$' and it carries current '$I$'. The ratio of magnetic moment of new coil to that of original coil is
Question 36 :
Two long parallel wires are separated by a distance of $2.50 cm$.The force per unit length that each wire exerts on the other is $4.00\times {10}^{-5}N/m$, and the wires repel each other. The current in one wire is $0.600 A$. What is the current in the second wire?
Question 37 :
A photon of energy E ejects a photoelectron from a metal surface whose work function is $W_0.$ If this electron enters into a uniform magnetic field of induction B in a direction perpendicular to the field and describes a circular path of radius r, then the radius r is given by (in the usual notation)
Question 38 :
A drop of oil of mass 2 ng is kept stationary in between two plates 2 cm apart. A potential difference is 2 kV is applied. The number of electrons it gained is<br>
Question 39 :
A coil of resistance $40\Omega$ is connected to a galvanometer of $160\Omega$ resistance. The coil has radius $6$mm and turns $100$. This coil is placed between the poles of a magnet such that magnetic field is perpendicular to coil. If coil is dragged out then the charge through the galvanometer is $32\mu C$. The magnetic field is?
Question 40 :
Let $[\varepsilon_o]$ denote the dimensional formula of the permittivity of the vacuum, and $[\mu_o]$ that of the permeability of the vacuum. If M$=$mass, L$=$length, T$=$time and I$=$ electric current.
Question 41 :
A charged particle moves with a constant velocity $(\hat{i}+\hat{j})$m/s in a magnetic field $\vec{B}=(2\hat{i}+3\hat{k})$and uniformelectric field $\vec{E}=(a\hat{i}+b\hat{j}+c\hat{k})$N/C, then $($assuming all quantities in S.I. unit$) :$
Question 42 :
A long solenoid has $200$ turns per $cm$ and carries a current of $2.5\ Amp$. The magnetic field at its centre is ($\mu _{0}=4\pi \times 10^{-7} $Wb/ A-m)
