Question 1 :
In cyclotron, for a given magnet, radius of the semicircle traced by positive ion is directly proportional to__________. (v=velocity of positron ion)<br/>
Question 2 :
The number of turns per unit length in a toroid is $10^3$and current flowing in it is $\dfrac{1}{4\pi} A$, then the magnetic induction produced in it, is :
Question 3 :
The relation between voltage sensitivity $\sigma _{v}$ and the current sensitivity $\sigma _{i}$ of a moving coil galvanometer is (Given that $G$ is the resistance of the galvanometer)<br/>
Question 4 :
Best method to increase the sensitivity of the moving coil galvanometer is to decrease<br/>
Question 5 :
We have a galvanometer of resistance 25$\Omega$. It is shunted by a 2.5$\Omega$ wire, the part of total current that flows through the galvanometer is given as:
Question 7 :
Two streams of electrons are moving parallel to each other in the same direction. They_____<br/>
Question 8 :
Which of the following is based on mechanical effect of electric current?
Question 9 :
A long solenoid is formed by the winding $20\ turns/cm$. What will be the current necessary to produce a magnetic field of $20\ millitesla$ inside the solenoid?<br>($\dfrac { { \mu }_{ 0 } }{ 4\pi } ={ 10 }^{ -7 }tesla\quad -meter/ampere$)<br>
Question 10 :
The coil of the moving coil galvanometer is wound over an aluminium frame<br/>
Question 13 :
When a solenoid is activated, the force that moves the plunger is
Question 14 :
A wire of length $L$ is made in the form of a coil in a moving coil galvanometer. To have maximum sensitiveness the shape of the coil is <br/>
Question 16 :
A particle specified charge $(q/m)$ is projected from the origin of coordinates with initial velocity $[u\hat{i} - v\hat{j}].$ Uniform electric magnetic fields exists in the region along the +y direction, of magnitude $E$ and $B$. The particle will definitely return to the origin once if.
Question 17 :
How much length of a very wire is required to obtain a solenoid of length $I_0$ and inductance L :
Question 19 :
When a current carrying coil is placed in a uniform magnetic field of induction $B$, then a torque $\tau $ acts on it. If $I$ is the current, $n$ is the number of turns and $A$ is the face area of the coil and the normal to the coil makes an angle $\theta $ with $B$, Then<br/>
Question 20 :
A current I is passed through a solenoid of n turns per unit length. What is the magnetic filed inside the solenoid ? <br/>
Question 22 :
A large solenoid of windings of 400 turns per meter carries a current 5A. The magnetic field at the centre of the solenoid is about:
Question 23 :
A solenoid has length 0.4 cm, radius 1 cm and 400 turns of wire. If a current of 5 A is passed through this solenoid, what is the magnetic field inside the solenoid?
Question 24 :
If 6 mm is the distance moved by the thimble on the main scale for 6 rotations then pitch of the screw is :<br>
Question 25 :
A solenoid with a soft iron core is called a _____.
Question 27 :
A cubical region of space is filled with some uniform electric and magnetic fields. An electron enters the cube across one of its faces with velocity v, and a positron enters via opposite face with velocity -v. At this instant.
Question 28 :
Complete the following sentenceA current carrying solenoid behaves like a $\underline{          }$. 
Question 29 :
If a toroid uses bismuth for its core, the field in the core compared to that in empty core will be slightly
Question 30 :
The strength of the magnetic field of solenoid increases with the decrease in number of turns in the solenoid.<br><br>
Question 31 :
A device used for detecting small currents due to changing magnetic field is known as:
Question 33 :
Why does toroid have a higher magnetic field than a solenoid?
Question 35 :
Which rule is used to find the direction of magnetic field in a toroid?
Question 37 :
In a cyclotron, If a deuteron can gain an energy of 40 MeV, then a proton can an energy of:
Question 38 :
The magnitude of the magnetic field inside along solenoid is increased by
Question 39 :
Two streams of protons move parallel to eachother in the same direction. They will<br>
Question 41 :
A rectangular loop carrying a current $i$ is placed in a uniform magnetic field $B$. The area enclosed by the loop is $A$. If there are $n$ turns in the loop, the torque acting on the loop is given by<br/>
Question 42 :
A current of $10^{-7}$ ampere produces 50 division deflection in a galvanometer. Then its figure of merit will be<br>
Question 44 :
If a velocity has both perpendicular and parallel components while moving through a magnetic field, what is the path followed by a charged particle?
Question 45 :
The magnetic field lines inside the solenoid are in the form of
Question 46 :
The sensitivity of a moving coil galvanometer increases with the decrease in <br/>
Question 47 :
In a moving coil galvanometer, the magnetic pole pieces are made cylindrical and a soft iron core is placed at the centre of the coil,the purpose for doing so is:<br/>
Question 51 :
The force of repulsion between two parallel wires is fwhen each one of them carries a certain current I. If the current in each is doubled, the force between them would be
Question 53 :
Two parallel conductors P and Q of equal lengths carry currents I and $5I$ respectively in the same direction, then.
Question 54 :
A 90 cm long solenoid has six layers of windings of 450 turns each. If the diameter of solenoid is 2.2 cm and current carried is 6 A, then the magnitude of magnetic field inside the solenoid, near its centre is:
Question 55 :
On passing electric current in two long straight conductors in mutually opposite directions, the magnetic force acting between them will be<br>
Question 56 :
The cyclotron frequency of an electron grating in a magnetic field of 1 T is approximately :<br/>
Question 57 :
A bar magnet has a magnetic moment of $200 A m^2$. The magnet is suspended in a magnetic field of $0.30 N A^{-1} m^{-1}$. The torque required to rotate the magnet from its equilibrium position through an angle of $30^0$, will be then<br/>
Question 58 :
A circular loop of radius $1 m$ carries an electric current. Let $P$ and $Q$ be two points on the axis of the loop at distance $1 m$ and $7 m$ respectively from the center. If the magnetic field at P due to the current is $125 \ mT$, then the magnetic field at $Q$ will be about :<br/>
Question 59 :
The magnetic field  $\overline{dB}$ due to a small current element dl at a distance $\vec{r}$ and carrying current ‘i’ is<br/>
Question 60 :
Two particles having the same momentum enter at right angles into same magnetic field and travel in circular paths of radius $r_{1}$ and  $r_{2}$. The ratio of their charges is:<br/>
Question 61 :
Which of the following statement is not correct about two parallel conductors carrying equal currents in the same direction?<br>
Question 62 : <p>The radius of motion of charged particle oscillating in a magnetic field is</p>
Question 63 :
Two circular coils 1 and 2 are made from the same wire but the radius of 1stcoil is twice that of the 2ndcoil. What potential difference in volts should be applied across them so that the magnetic magnetic field at the centres is the same
Question 64 :
A galvanometer of resistance $50\Omega$ giving full scale deflection for a current of $10$ milliampere is to be changed into a voltmeter of range $100$V.<br>A resistance of ________$\Omega$ has to be connected in series with the galvanometer.<br>
Question 65 :
A long solenoid has $200$ turns per cm and carries a current $i$. The magnetic field at its centre is$6.28 \times 10^{-2} Wb/m^{2}$Another long solenoid has $100$ turns per cm and it carries a current $i/3$. The<br>value of the magnetic field at its centre is :
Question 66 :
Two parallel wires $1\ m$ apart carry currents of $1\ A$ and $3\ A$ respectively in opposite directions. The force per unit length acting between these two wires is
Question 67 :
Imagine that you are sitting in a room with your back to one wall and that an electron beam traveling horizontally from the back wall towards the front one is deflected towards the right. What is the direction of the magnetic induction field that exists in the room? <br/>
Question 68 :
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 69 :
Electron of mass m and charge $q$ is traveling with a speed along a circular path of radius $r$ at right angles to a uniform magnetic field of intensity B. If the speed of the electron is doubled and the magnetic field is halved the resulting path would have a radius. <br>
Question 70 :
The force of repulsion between two parallel wires is $f$ when each one of them carries a certain current $I$. If the current in each is doubled, the force between them would be 
Question 71 :
Assertion : An electron is not deflected on passing through certain region of space. This observation confirms that there is no magnetic field in that region.<br>Reason : The deflection of electron depends on angle between velocity of electron and direction ofmagnetic field.
Question 72 :
A current carrying ring is placed in a magnetic field. The direction of the field is perpendicular to the plane of the ring. Which of the following correct for this?<br/>
Question 73 :
A deuteron of kinetic energy $50\ keV$ is describing a circular orbit of radius $0.5$ metre in a plane perpendicular to the magnetic field $B$. The kinetic energy of the proton that describes a circular orbit of radius $0.5$ metre in the same plane with the same $B$ is
Question 74 :
Two similar circular loops of radius $R$, are lying concentrically with their planes at right angles to each other. The currents flowing in them are $I$ and $I\sqrt{3}$ respectively. The magnetic field at the centre of the coil is :
Question 75 :
The force per unit length between two long straight conductors carrying currents 3 A each in the same direction and separated by a distance of 2.0 cm is :<br/>
Question 76 :
The correct relation between $B$ and $M$ for a small current-carrying coil is :<br/>
Question 78 :
An unknown particle is being studied in a magnetic field of variable intensity and direction. When the magnetic field is turned off, the particle is observed to move toward the earth. When the magnetic field is turned on, the particle is observed to continue to move toward the earth, no matter the strength or the direction of the magnetic field. Which of the particles listed below is most likely the unknown particle?
Question 79 :
A magnetic needle kept non parallel to the magnetic field in a non uniform magnetic field experience.
Question 80 :
The coercivity of a small bar magnet is $4\times { 10 }^{ 3 }A/m$. It is inserted inside a solenoid of $500$ turns and length $1m$ to demagnetise it. The amount of current to be passed through the solenoid will be :
Question 81 :
A charged particle of charge $5$ $mC$ and mass $5$ $gm$ is moving with a constant speed $5$ $ms^{-1}$ in a uniform magnetic field on a curve $x^{2}+y^{2}=25$ . Where $x$ and $y$ are in meter. The value of magnetic field is:<br/>
Question 82 :
The total momentum of electrons in a straight wire of length $l= 1000 m$ carrying a current I$= 70 A$, will be (in $N-s$)<br/>
Question 83 :
An electron is traveling along the x-direction. It encounters a magnetic field in the y-direction. Its subsequent motion will be<br>
Question 84 :
The torque on a bar magnet due to the earth's magnetic field ismaximum when the axis of the magnet is
Question 85 :
A one meter long wire is lying at right angles to the magnetic field. A force of $1\ kg\ wt$ is acting on it in a magnetic field of $0.98\ Tesla$. The current flowing in it will be
Question 86 :
An electron enters a region where electrons field is $20\ N/C$ and magnetic field is $5\ T$. If electrons passes undeflected through the region, then velocity of electrons will be
Question 87 :
If a proton, deutron and $\alpha-$particle or being accelerated by the same potential difference entersperpendicular to the magnetic field, then the ratio of their kinetic energy is<br>
Question 88 :
A beam consisting of protons and electrons moving at the same speed goes through a thin region in which there is a magnetic field perpendicular to the beam. Theprotons and the electrons
Question 89 :
A helium nucleus makes a full rotation in a circle of radius $0.8 m$ in $2 sec$. The value of the magnetic field induction $B$ in tesla at the centre of circle will be<br>
Question 90 :
The net magnetic flux through any closed surface, kept in a magnetic field is
Question 91 :
A closely wound solenoid of $800$ turns and area of cross section $2.5\times 10^{-4} m^2$ carries a current of $3A$. Explain the sense in which the solenoid acts like a bar magnet. What is its associated magnetic moment?
Question 92 :
If a ferromagnetic material is inserted in a current carrying solenoid,the magnetic field of solenoid
Question 93 :
Two wires carry currents of  $100\  A$ and  $200\  A$ respectively and they repel each other with a force of  $0.4\  N/m$. The distance between them will be :<br/>
Question 94 :
Two particles of different masses $m_{1}$ and $m_{2}$ , different charges $Q_{1}$ and $Q_{2}$ , are accelerated through the same potential difference and then enter a uniform magnetic field in a direction perpendicular to the field. If they trace circular paths of same radius, then the ratio of their masses ($m_{1}$/$m_{2}$ ) must be :<br/>
Question 95 :
A cell is connected between two points of a uniformly thick circular conductor and $i_1$ and $i_2$ are the currents flowing in two parts of the circular conductor of radius a. The magnetic field at the centre of the loop will be
Question 96 :
The period of revolution of a charged particle inside a cyclotron does not depend on :
Question 97 :
A conducting gas is in the form of a long cylinder. Current flows through the gas along the length of the cylinder. The current is distributed uniformly across the cross-section of the gas. Disregard thermal and electrostatic forces among the gas molecules. Due to the magnetic fields set up inside the gas and the forces which they exert on the moving ions, the gas will tend to<br>
Question 98 :
Two circular coils are made of two identical wires of the same length. If the number of turns of the two coils are $4$ and $2$, then the ratio of magnetic inductions at the centre will be respectively :<br/>
Question 99 :
The force between two parallel conductors, each of length $50 m$ and distant $20 cm$ apart, is $1 N$. If the current in one conductor is double than that in another one, then their values will respectively be :<br/>
Question 100 :
A closely wound solenoid of 800 turns and area of cross section $2.5 \times 10^{-4}m^2$ carries a current of $3.0A$. Explain the sense in which the solenoid acts like a bar magnet. What is its associated magnetic moment?
