COMEDK 2022

During the phenomenon of resonance

A DC ammeter and a hot wire ammeter are connected to a circuit in series. When a direct current is passed through circuit, the DC ammeter shows 6 A. When AC current flows through circuit, what is the average readings in DC ammeter and the A...

A series L-C-R circuit is connected to an AC source of 220 V and 50 Hz shown in figure. If the readings of the three voltmeters \(V_1,V_2\) and \(V_3\) are 65 V, 415 V and 204 V respectively, the value of inductance and capacitance will be

An alternating voltage = 200 \(\sin 100t\) is applied to a series combination of \(R=30\Omega\) and an inductor of 400 mH. The power factor of the circuit is,

The AC voltage across a resistance can be measured using a

During \(\alpha\)-decay, atomic mass of parent nuclei is

Which of the following series spectrum of hydrogen atom lies in ultraviolet region?

The wavelength of the second line of Balmer series is 486.4 nm. What is the wavelength of the first line of Lyman series?

If R and C denote resistance and capacitance of a material, then the dimension of CR will be :

In the network shown in figure, the equivalent capacitance between points P and Q is

A bullet of mass $m$ hits a mass \(M\) and gets embedded in it. If the block rises to a height \(h\) as a result of this collision, the velocity of the bullet before collision is

From a circular disc of radius R, a square is cut out with a radius as its diagonal. The centre of mass of remaining portion is at a distance (from the centre)

Maximum amplitude of message signal in amplitude modulation is 20 cm. If the amplitude of carrier wave is 40 cm, then modulation index of modulated wave is

A galvanometer having a resistance of 4 \(\Omega\) is shunted by a wire of resistance 2 \(\Omega\). If the total current is 1.5 A, the current passing through shunt is

A cell of emf 2 V is connected with a load of resistance 1.5 \(\Omega\). The power delivered by the cell to the load is maximum, then power transferred to the load is

Ultraviolet light of wavelength 99 mm falls on a metal plate of work function 1.0 eV. If the mass of the electron is 9.1 \(\times\) 10\(^{-31}\) kg, the wavelength of the fastest photoelectron emitted is

If K\(_1\) and K\(_2\) are maximum kinetic energies of photoelectrons emitted when lights of wavelengths \(\lambda_1\) and \(\lambda_2\), respectively incident on a metallic surface and \(\lambda_1=3\lambda_2\), then

A copper and a steel wire of same diameter are connected end to end. A deforming force F\(_1\) is applied to the wire which causes an elongation of 1 cm. The two wires will have

A force F applied on the wire of radius r and length L and change in the length of the wire is \(l\). If the same force F is applied on the wire of the same material and radius 4r and length \(4l\), then change in length of the other wire i...

Television frequencies are of the order of 100 MHz, while radio frequencies are of the order of 1 MHz. Using these as typical frequencies, the ratio of the emf generated in a loop antenna by a television wave to that generated by a radio wa...

A circular coil of 20 turns and radius 10 cm is placed in a uniform magnetic field of 0.10 T normal to the plane of the coil. If the current in the coil is 5 A, then the average force on each electron in the coil due to the magnetic field i...

Speed of electromagnetic wave in a medium having relative permittivity \(\varepsilon_r\) and relative permeability \(\mu_r\) is (speed of light in air, \(c=3\times10^8\) m/s)

A 30 mW laser beam has a cross-sectional area of 15 mm2. The magnitude of the maximum electric field in this electromagnetic wave is given by
[Permuittivity of space, \(\varepsilon_0=9\times10^{-12}\)
Speed of light, \(c=3\times10^8\) m/s]

Which of the following diagram represents the variation of the electric field with distance r from the centre of a uniformly charged non-conducting sphere of radius R?

Charge on electron is

Two charged spheres of \(-20\mu\)C and \(60\mu\)C are kept at a certain distance. They are touched and kept again at the same distance. What is the ratio of force experienced before and after?

A raft of density 600 g/m\(^3\) and mass 120 kg floats in water. How much weight can be put on the raft to make it just sink?

Water is poured in a tank through a cylindrical tube of area of cross-section A and ejecting water at a constant speed 4 m/s. the tank contains a hole of area \(\frac{A}{2}\) at bottom. Level of water in the tank will not go up beyond

If the earth were to spin faster, acceleration due to gravity at the poles

The height at which the acceleration due to gravity becomes \(\frac{g}{16}\) (where, g = acceleration due to gravity on the surface of the earth) in terms of R is, if R is the radius of earth.

The escape velocity of a projectile on the earth's surface is 11.2 km/s. A body is projected out with thrice this speed. The speed of the body far away from the earth will be

If heat engine is filled at temperature 27\(^\circ\)C and heat of 100 k cal is taken from source at temperature 677\(^\circ\)C. Work done (in J) is

From the following p-V diagram, an ideal gas undergoing a change of state from A to B. Four different processes I, II, III and IV as shown in the figure may lead to same change of state.

An ideal gas is taken through the cycle A \(\to\) B \(\to\) C \(\to\) A, as shown in the figure. If the net heat supplied to the gas in the cycle is 5 J, the work done by the gas in the process
C \(\to\) A is,

The average kinetic energy of a molecule in air at room temperature of 20\(^\circ\)C

There are two identical containers C\(_1\) and C\(_2\) containing to identical gases. Gas in C\(_1\) is reduced to half of its original volume adiabatically, while the gas in container C\(_2\) is also reduced to half of its initial volume i...

In which mode of transmission, the heat waves travel along straight line with the speed of light?

Consider a compound slab consisting of two different materials having equal lengths, thickness and thermal conductivities K and 2K respectively. The equivalent thermal conductivity of the slab is

With what minimum acceleration can a fireman slide down a rope while breaking strength of the rope is \(\frac{2}{3}\) of the weight?

A bar magnet of length \(6 \mathrm{~cm}\), is placed in the magnetic meridian with \(N\) pole, pointing towards the geographical north. Two neutral points, separated by a distance of \(8 \mathrm{~cm}\) are obtained on the equitorial axis of...

The displacement \(x\) of a particle in a straight line motion is given by \(x=1-t-t^2\). The correct representation of the motion is

Two guns P and Q can fire bullets at speeds 2 km/s and 4 km/s, respectively. From a point on a horizontal ground, they are fired in all possible directions. The ratio of maximum or areas covered by the bullets fired by the two guns, on the ...

A car is moving with a speed of 54 km/h. If after 3 s, the driver applies brakes and it stops, then how much distance is covered by the car before coming to rest?

An electric current $I$ enters and leaves a uniform circular wire of radius $r$ through diametrically opposite points. A charged particle \(q\) moves along the axis of circular wire passes through its centre with speed \(v\). The magnetic f...

A regular hexagon of side \(m\) which is a wire of length 24 m is coiled on that hexagon. If current in hexagon is \(I\), then the magnetic moment,

A point object is placed on the optic axis of a convex lens of focal length \(f\) at a distance of \(2f\) to the left of it. The diameter of the lens is \(d\). An eye is placed at a distance of \(3f\) to the right of the lens and a distance...

A plane glass mirror of thickness 3 cm of material of \(\mu=\frac{3}{2}\) is silvered on the black surface. When a point object is placed 9 cm from the front surface of the mirror, then the position of the brightest image from the front sur...

A disc of moment of inertia 4 kg - m\(^2\) revolving with 16 rad/s is placed on another disc of moment of inertia 8 kg - m\(^2\) revolving 4 rad/s. The angular frequency of composite disc

For CE transistor amplifier, the audio signal voltage across the collector resistance of 4 k\(\Omega\) is 5 V. If the current amplification factor of the transistor is 100 and base resistance is 2 k\(\Omega\), then input signal voltage is

Which of the following gate give the similar output as the output of circuit diagram shown in the figure?