List of top Questions asked in KEAM

A conducting ring of radius 1 m kept in a uniform magnetic field B of 0.01 T, rotates uniformly with an angular velocity 100 rad s\(^{-1}\) with its axis of rotation perpendicular to B. The maximum induced emf in it is

A step down transformer increases the input current 4 A to 24 A at the secondary. If the number of turns in the primary coil is 330, the number of turns in the secondary coil is

A bar magnet of moment of inertia \(9 \times 10^{-5} \text{ kg m}^2\) placed in a vibration magnetometer and oscillating in a uniform magnetic field \(16\pi^2 \times 10^{-5} \text{ T}\) makes 20 oscillations in 15 s. The magnetic moment of the bar magnet is

If a magnetic dipole of moment M situated in the direction of a magnetic field B is rotated by \(180^\circ\), then the amount of work done is

The polarity of induced emf is given by

If the radius of the dees of cyclotron is \(r\), then the kinetic energy of a proton of mass \(m\) accelerated by the cyclotron at an oscillating frequency \(\nu\) is

In an LCR series circuit, at resonance

Identify the correctly matched pair

If the ammeter A shows a zero reading in the circuit shown below, the value of resistance R is

Five cells each of emf E and internal resistance \(r\) send the same amount of current through an external resistance R whether the cells are connected in parallel or in series. Then the ratio \( \left( \frac{R}{r} \right) \) is

The magnitude of the magnetic field inside a long solenoid is increased by

The power dissipated in the transmission cables carrying current I and voltage V is inversely proportional to

A rigid container with thermally insulated walls contains a gas and a coil of resistance 50 \(\Omega\), carrying a current of 1 A. The change in internal energy of the gas after 2 minutes will be

The time period of revolution of a charge \(q_1\) and of mass \(m\) moving in a circular path of radius \(r\) due to Coulomb force of attraction with another charge \(q_2\) at its centre is

A point charge of 2 C experiences a constant force of 1000 N when moved between two points separated by a distance of 2 cm in a uniform electric field. The potential difference between the two points is

In the network shown below, if potential across XY is 4 V, then the input potential across AB is

A plane square sheet of charge of side 0.5 m has uniform surface charge density. An electron at 1 cm from the centre of the sheet experiences a force of \( 1.6 \times 10^{-12} \) N directed away from the sheet. The total charge on the plane square sheet is (\( \epsilon_0 = 8.854 \times 10^{-12} \text{ C}^2\text{m}^{-2}\text{N}^{-1} \))

The energy stored in a capacitor of capacitance C having a charge Q under a potential V is

The electrostatic force between two point charges is directly proportional to the

The total energy of the particle executing simple harmonic motion of amplitude A is 100 J. At a distance of 0.707 A from the mean position, its kinetic energy is

Identify the wrong statement from the following

Two travelling waves, \( y_1 = A \sin [ k ( x + ct ) ] \) and \( y_2 = A \sin [ k ( x - ct ) ] \) are superposed on a string. The distance between adjacent antinodes is

If a stretched wire is vibrating in the second overtone, then the number of nodes and antinodes between the ends of the string are respectively

Pick out the correct statement in the following with reference to stationary wave pattern

If the differential equation for a simple harmonic motion is \( \frac{d^2y}{dt^2} + 2y = 0 \), the time-period of the motion is