List of top Questions asked in KEAM- 2025

In which of the following spectral region Balmer series lines are observed for atomic hydrogen
The band gap energy of silicon is
When a radioactive material emits an \(\alpha\)-particle, its position in the periodic table
In a plane electromagnetic wave, the magnetic field is given by \(B = 400 \times 10^{-6}\sin[(4.0 \times 10^{-4})(t - x/c)]\). The peak value of electric field (in V m\(^{-1}\)) is
Ionization potential of hydrogen atom is 13.6 eV. Hydrogen atom in the ground state initially is excited by monochromatic radiation of photon energy 12.75 eV. The number of spectral lines emitted by the hydrogen atom, according to Bohr’s theory will be
When blue light is incident on a certain metal surface, photoelectrons are emitted. When green light is incident on the same metal surface, no electrons are emitted. If the same metallic surface is exposed to yellow light,
A convex lens having power \(P\) is cut into two halves perpendicular to the principal axis. Then the power of each piece is
In Young’s double slit experiment performed in air medium, the fringe width observed is 1.4 mm. If the entire arrangement is kept in a liquid medium of refractive index 1.4, then the fringe width (in mm) will be
Three capacitors each of capacitance \(12\,\mu F\), are connected in series. When this combination is connected to a battery of \(12\,V\), the charge drawn from the battery is
An electric cell does 10 J of work in carrying a charge of 5 C around a simple closed circuit. The electromotive force of the cell is
An iron ring is held horizontally and a bar magnet is dropped gently through the ring with its length coinciding with the axis of the ring. The acceleration of the freely falling magnet (\(g\) = acceleration due to gravity) is
When a proton moves in a uniform magnetic field such that its velocity has a component along the direction of magnetic field, its trajectory will be a
A wire of length 1.2 m carrying a current of 4 A, when placed in a uniform magnetic field 5 T experiences a force of 12 N. Then the angle between the direction of current and magnetic field is
Pick out the INCORRECT statement
A closed organ pipe and an open organ pipe have the same length. The ratio of the frequencies in their third mode of vibrations is
The temperature at which the r.m.s. velocity of oxygen molecule is equal to that of hydrogen molecule at 20 K is
A point charge \(-q\) is placed at a distance \(x\) from an isolated conducting plane. The electric field at any point \(P\) on the other side of the plane is directed
If the value of \(C_p/C_v\) is unity in the equation \(PV^\gamma = \text{constant}\), then the process is
A particle executes linear simple harmonic motion and its potential energy (P.E.), kinetic energy (K.E.), total energy (T.E.) are measured as functions of displacement \(x\) from the mean position at the origin. Then
A shell travelling along a parabolic path in the gravitational field of the earth undergoes explosion in mid air. The centre of mass of the fragments will move
Two bodies of masses \(m\) and \(4m\) are kept at a distance of \(x\). The distance on the axial point from \(m\) at which the gravitational field is zero is
The total pressure \(P\) inside an air bubble of radius \(r\) at a depth \(h\) below the surface of liquid of density \(\rho\) is (T = surface tension of liquid, \(P_0\) = atmospheric pressure)
Work done in a stretched wire is
The ratio of radius of gyration of a circular ring to that of a circular disc, each of same mass and same radius about their respective central axes is
Pick out the INCORRECT statement from the following