List of top Physics Questions asked in KCET

The energy gap of an LED is 2.4 eV. When the LED is switched ‘ON’, the momentum of the emitted photons is

In the situation shown in the diagram, magnitude of q << | Q | and r>>a. The net force on the free charge -q and net torque on it about O at the instant shown are respectively
[ p = 2aQ is the dipole moment ]

A 60 W source emits monochromatic light of wavelength 662.5 nm. The number of photons emitted per second is

In the Young’s double slit experiment, the intensity of light passing through each of the two double slits is 2 × 10^-2 Wm^-2. The screen-slit distance is very large in comparison with slit-slit distance. The fringe width is β. The distance between the central maximum and a point P on the screen is \(\frac{\beta}{3}\). Then the total light intensity at that point is

An unpolarised light of intensity I is passed through two polaroids kept one after the other with their planes parallel to each other. The intensity of light emerging from second polaroid is \(\frac{I}{4}\). The angle between the pass axes of the polaroids is

In the Rutherford’s alpha scattering experiment, as the impact parameter increases, the scattering angle of the alpha particle

The ratio of the magnitudes of electric field to the magnetic field of an electromagnetic wave is of the order of

In an experiment to study photo-electric effect the observed variation of stopping potential with frequency of incident radiation is as shown in the figure. The slope and y-intercept are respectively

For a point object, which of the following always produces virtual image in air?

Total impedance of a series LCR circuit varies with angular frequency of the AC source connected to it as shown in the graph. The quality factor Q of the series LCR circuit is

An equiconvex lens made of glass of refractive index \(\frac{3}{2}\) has focal length f in air. It is completely immersed in water of refractive index \(\frac{4}{3}\). The percentage change in the focal length is

A square loop of side 2 cm enters a magnetic field with a constant speed of 2 cm s^-1 as shown. The front edge enters the field at t = 0s. Which of the following graph correctly depicts the induced emf in the loop?
( Take clockwise direction positive )

In series LCR circuit at resonance, the phase difference between voltage and current is

A proton and an alpha-particle moving with the same velocity enter a uniform magnetic field with their velocities perpendicular to the magnetic field. The ratio of radii of their circular paths is

The torque acting on a magnetic dipole placed in uniform magnetic field is zero, when the angle between the dipole axis and the magnetic field is _____.

A wire of resistance R is connected across a cell of emf ε and internal resistance r. The current through the circuit is I. In time t, the work done by the battery to establish the current I is

The resistance of a carbon resistor is 4.7 kΩ ± 5% . The colour of the third band is

A charged particle is subjected to acceleration in a cyclotron as shown. The charged particle undergoes increase in its speed

A block of mass m is conducted to a light spring of force constant k. The system is placed inside a damping medium of damping constant b. The instantaneous values of displacement, acceleration and energy of the block are x, a and E respectively. The initial amplitude of oscillation is A and ω' is the angular frequency of oscillations. The incorrect expression related to the damped oscillations is

Pressure of ideal gas at constant volume is proportional to _______.

A stretched wire of a material whose Young's modulus Y = 2 × 10¹¹ Nm^-2 has Poisson's ratio of 0.25. Its lateral strain ε_l = 10^-3. The elastic energy density of the wire is

When a planet revolves around the Sun, in general, for the planet

A positively charged glass rod is brought near uncharged metal sphere, which is mounted on an insulated stand. If the glass rod is removed, the net charge on the metal sphere is

A closed water tank has cross-sectional area A. It has small hole at a depth of h from the free surface of water. The radius of the hole is r so that r << \(\sqrt{\frac{A}{\pi}}\). If P_o is the pressure inside the tank above water level, and P_a is the atmospheric pressure, the rate of flow of the water coming out of the hole is [ ρ is the density of water]

Seven identical discs are arranged in a planar pattern, so as to touch each other as shown in the figure. Each disc has mass ‘m’ radius R. What is the moment of inertia of system of six discs about an axis passing through the centre of central disc and normal to plane of all discs?