List of top Questions asked in COMEDK UGET

A neutron makes a head-on elastic collision with a lead nucleus. The ratio of nuclear mass to neutron mass is 206. The fractional change in kinetic energy of a neutron is:
The force between two electric point charges at rest in air is \( F_1 \). When the same arrangement is kept inside water, the force between them is \( F_2 \). Which of the following statement is correct?
A circular loop of area 0.04 m\(^2\) carrying a current of 10 A is held with its plane perpendicular to a magnetic field induction of 0.4 T. Then the torque acting on the circular loop is:
A battery is made of 12 cells having emf 5 V each. If three cells are unknowingly connected wrong, the resultant emf of the battery will be:
A wheel is free to rotate about a horizontal axis through \( O \). A force of 200 N is applied at a point \( P_2 \) from the center \( O \). \( OP \) makes an angle of 55° with the \( x \)-axis and the force is in the plane of the wheel making an angle of 25° with the horizontal axis. What is the torque?
A hockey player hits the ball at an angle of 37° from the horizontal with an initial speed of 40 m/s (a right-angled triangle with one of the angles being 37° and their sides in the ratio of 6 : 8 : 10). Assume that the ball is in a vertical plane. The time at which the ball reaches the highest point of its path is:
A light having wavelength 6400 \( \text{\AA} \) is incident normally on a slit of width 2 mm. Then the linear width of the central maximum on the screen kept 2 m from the slit is:
What feature of the infrared waves make it useful for the haze photography?

\( F_A, F_B, \) and \( F_C \) are three forces acting at point \( P \) as shown in the figure. The whole system is in equilibrium state. The magnitude of \( F_A \) is:

A drone is flying due west, a little above the train, with a speed of 10 m/s. A 270 meter long train is moving due east at a speed of 20 m/s. The time taken by the drone to cross the train is:
If the resultant of all external forces acting on a system of particles is zero, then from an inertial frame one can surely say that:
What should be the inductance of an inductor connected to 200 V, 50 Hz source so that the maximum current of \( \sqrt{2} \, \text{A} \) flows through it?
The radius of the current carrying circular coil is doubled keeping the current passing through it the same. Then the ratio of the magnetic field produced at the centre of the coil before the doubling of the radius to the magnetic field after doubling of the radius is:
The nucleus of a helium atom travels along the inside of a straight hollow tube 4 m long which forms part of a particle accelerator. If one assumes uniform acceleration, how long is the particle in the tube if it enters at a speed of 2000 m/s and leaves at 8000 m/s?
The reverse current in the semiconductor diode changes from 20 \(\mu\text{A}\) to 40 \(\mu\text{A}\) when the reverse potential is changed from 10 V to 15 V, then the reverse resistance of the junction diode will be:

In the given circuit the diode \( D_1 \) and \( D_2 \) have the forward resistance 250 \(\Omega\) and infinite backward resistance. When they are connected to the source as shown, the current passing through the 175 \(\Omega\) resistor is:

The SI unit of electrical conductivity is:
Two black bodies P and Q have equal surface areas and are kept at temperatures \( 127^\circ C \) and \( 27^\circ C \) respectively. The ratio of thermal power radiated by A to that by B is:
In the head-on collision of two alpha particles \( \alpha_1 \) and \( \alpha_2 \) with the gold nucleus, the closest approaches are 31.4 fermi and 94.2 fermi respectively. Then the ratio of the energy possessed by the alpha particles \( \alpha_2 / \alpha_1 \) is:
Find the pole strength of a magnet of length 2 cm, if the magnetic field strength \( B \) at distance 10 cm from the centre of a magnet on the axial line of the magnet is \( 10^{-4} \, \text{T} \).
The acceleration due to gravity at a height of 7 km above the earth is the same as at a depth \( d \) below the surface of the earth. Then \( d \) is:
A tentative explanation of observations without assuming that it is true is called:
The molecules of a given mass of a gas have root mean square speed of 120 m/s at 88°C and 1 atmospheric pressure. The root mean square speed of the molecules at 127°C and 2 atmospheric pressure is:
The ground state energy of hydrogen atom is -13.6 eV. If the electron jumps from the 3rd excited state to the ground state, then the energy of the radiation emitted will be:
What will be the change in wave length, if a light of wave length 600 nm travels from air enters a medium of refractive index 1.5 and continues its journey through that medium?