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A body is released from the top of a tower of height $h$. It takes $t$ sec to reach the ground. Where will be the ball after time $t/2$ sec?
When a proton is released from rest in a room, it starts with an initial acceleration $a_0$ towards the east. When it is projected towards the north with a speed $v_0$, it moves with initial acceleration $3a_0$ towards east. The electric and magnetic fields in the room are:
Two polaroids $P_1$ and $P_2$ are placed with their axis perpendicular to each other. Unpolarised light $I_o$ is incident on $P_1$. A third polaroid $P_3$ is kept in between $P_1$ and $P_2$ such that its axis makes an angle $45^\circ$ with that of $P_1$. The intensity of transmitted light through $P_2$ is
A particle mass m, charge Q, and kinetic energy T enter a transverse uniform magnetic field of induction $\vec{B}$. After 3 sec the kinetic energy of the particle will be:
A closed-loop PQRS carrying a current is placed in a uniform magnetic field. If the magnetic forces on segments PS, SR and RO (RQ) are $F_1$, $F_2$ and $F_3$ respectively and are in the plane of the paper and along with the directions shown, the force on the segment QP is
In order to pass 10% of the main current through a moving coil galvanometer of 99 ohms, the resistance of the required shunt is:
The resistance of an ideal voltmeter is:
A galvanometer having a resistance of $8\ \Omega$ is shunted by a wire of resistance $2\ \Omega$. If the total current is $1\ \text{A}$, the part of it passing through the shunt will be:
If an ammeter A reads 2 A and the voltmeter V reads 20 V, what is the value of resistance R? (Assuming finite resistances of ammeter and voltmeter)
A voltmeter has a range $V$ with a series resistance $R$. With a series resistance $2R$, the range is $V'$. The correct relation between $V$ and $V'$ is:
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?
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:
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?
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:
The radius of a nucleus of a mass number $A$ is directly proportional to:
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 $\vec{B}$?
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:
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)