Browse and search thousands of solved questions for your preparation.
Free questions with full explanations — locked behind signup to protect quality.
The current flowing in a coil of resistance $90~\Omega$ is to be reduced by $90\%$. What value of resistance should be connected in parallel with it?
The nuclei $_{6}^{13}\text{C}$ and $_{7}^{14}\text{N}$ can be described as:
A galvanometer of $50~\Omega$ resistance has 25 divisions. A current of $4 \times 10^{-4} \text{ A}$ gives a deflection of one division. To convert this galvanometer into a voltmeter having a range of $25 \text{ V}$, it should be connected with a resistance of:
A beam of electrons passes un-deflected through mutually perpendicular electric and magnetic fields. Where do the electrons move if the electric field is switched off and the same magnetic field is maintained?
When a charged particle with velocity $\vec{v}$ is subjected to an induction magnetic field $\vec{B}$, the force on it is non-zero. What does this imply?
Two circular coils 1 and 2 are made from the same wire but the radius of the 1st coil is twice that of the 2nd coil. What is the ratio of the potential difference applied across them so that the magnetic field at their centres is the same?
A long wire carrying a steady current is bent into a circular loop of one turn. The magnetic field at the center of the loop is $B$. It is then bent into a circular coil of $n$ turns. The magnetic field at the centre of this coil of $n$ turns will be:
An electron is moving in a circular path under the influence of a transverse magnetic field of $3.57 \times 10^{-2}$ T. If the value of $e/m$ is $1.76 \times 10^{11}$ C/kg, the frequency of revolution of the electron is:
The radius of a nucleus of a mass number $A$ is directly proportional to:
Two similar coils of radius $R$ are lying concentrically with their planes at right angles to each other. The currents flowing in them are $I$ and $2I$, respectively. The resultant magnetic field induction at the centre will be:
In the product $\vec{F} = q(\vec{v} \times \vec{B}) = q\vec{v} \times (B\hat{i} + B\hat{j} + B_0\hat{k})$. For $q=1$ and $\vec{v} = 2\hat{i} + 4\hat{j} + 6\hat{k}$ and $\vec{F} = 4\hat{i} - 20\hat{j} + 12\hat{k}$, what will be the complete expression for $\vec{B}$?
A millivoltmeter of $25 \text{ mV}$ range is to be converted into an ammeter of $25 \text{ A}$ range. The value (in ohm) of necessary shunt will be:
The shape of the magnetic field lines due to an infinite long, straight current carrying conductor is:
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 used in the cyclotron and the kinetic energy ($K$) of the proton beam, produced by it, are given by:
A strong magnetic field is applied along the direction of the velocity of an electron. The electron would move along:
A closely packed coil having 1000 turns has an average radius of 62.8 cm. If the current carried by the wire of the coil is 1 A, the value of the magnetic field produced at the centre of the coil will be nearly: (permeability of free space = $4\pi \times 10^{-7}$ H/m)
A long straight wire of length $2 \text{ m}$ and mass $250 \text{ g}$ is suspended horizontally in a uniform horizontal magnetic field of $0.7 \text{ T}$. The amount of current flowing through the wire will be: ($g=9.8 \text{ m s}^{-2}$)
Two very long, straight, parallel conductors A and B carry current of 5 A and 10 A respectively and are at a distance of 10 cm from each other. The direction of the current in the two conductors is the same. The force acting per unit length between two conductors is: ($\mu_0=4\pi \times 10^{-7}$ SI unit)
The magnetic field on the axis of a circular loop of radius 100 cm carrying current I = √2 A, at a point 1 m away from the centre of the loop is given by:
A very long conducting wire is bent in a semi-circular shape from A to B as shown in the figure. The magnetic field at the point P for steady current configuration is given by: