COMEDK 2026 Afternoon Shift

An electronic device operates at 2 MHz . The oscillating circuit has an inductance $20 \times 10^{-5} \mathrm{H}$. What is the capacitive reactance of the resonant circuit?

A source of alternating emf $\varepsilon=\varepsilon_0 \sin (\omega t)$ is connected to a capacitor. Then the instantaneous current in the circuit is: ˋ

In a given circuit, the instantaneous values of the alternating voltage and current are $V=0.5 \sin \left(80 \pi t+\frac{\pi}{3}\right)$ volt and $I=0.5 \sin (80 \pi t)$ ampere respectively. Find the average power consumed in that circuit.

What is the frequency of the electron in the first orbit of hydrogen atom of orbital radius $0.5 \times 10^{-10} \mathrm{~m}$, if its orbital velocity in that orbit is $2.2 \times 10^6 \mathrm{~ms}^{-1}$.

The main function of cadmium used in the nuclear reactor is:

The atomic mass of an element $10 X^{20}$ is 19.98170 amu. The binding energy per nucleon of that element is: [given mass of neutron = 1.00867amu and mass of proton = 1.00783 amu and 1amu = 931 MeV ]

If the ratio of the nuclear radii of two atoms is $2: 3$ then the ratio of their mass numbers is:

A hydrogen atom absorbs energy and rises to $n=3$ state from its ground state $n=1$. If the potential energy of the atom at its ground state is -13.6 eV , find the wave length emitted by it when it returns to its ground state:
{Planck's con...

A capacitor of capacitance $8 \mu \mathrm{~F}$ is fully charged by connecting it to a source of 200 V . It is then disconnected from the supply and connected to an uncharged capacitor of capacitance $4 \mu \mathrm{~F}$. The electrostatic en...

The dimensional formula for specific resistance is:

A parallel combination of ' $n$ ' cells of emf ' $E$ ' and internal resistance ' $r$ ' each, are connected across the external resistance ' $R$ '. If the external resistance ' $R$ ' is negligibly small, then the current ' $I$ ' through the ...

An electric coil is rated $400 \mathrm{~W}, 200 \mathrm{~V}$. It is cut into two equal parts and connected in parallel to the same source of 200 V . Calculate the percentage increase in energy produced per second.

The voltage - current graph for a metal wire of uniform area of cross section at two different temp $T$ and $T^{\prime}$ is shown.
Then choose the correct statement:

The basic principle used behind the working of electron microscope is:

When metal of work function 1.4 eV is exposed to a radiation, the maximum kinetic energy of the electron emitted is 0.4 eV . The stopping potential required is:

The variation of the stopping potential ( $\mathrm{V}_{\mathrm{o}}$ ) with the frequency of incident radiation( $n$ ) is as given below.
[no - threshold frequency. h - Planck's constant e-electronic charge] then the slope of the graph AB wi...

A wire, made of a certain material of length-l and area of cross section-a can withstand a maximum load $=\mathrm{W}$ without breaking. If, another wire of the same material and crosssectional area is used with double the original length, w...

When a current of 2.5 A passes through the primary coil of a transformer of 200 number turns, the magnetic flux linked with the secondary coil having 400 turns is $600 \times 10^{-6} \mathrm{~T} \mathrm{~m}^2$. Find the induced emf in the s...

A metallic circular loop is placed with its plane perpendicular to a uniform magnetic field of 0.3 T . If the radius of the loop decreases at a constant rate of $2 \mathrm{~mm} \mathrm{~s}^{-1}$, what will be the induced emf in the loop, wh...

Two point charges $P=+25 \mu C$ and $Q=-16 \mu C$ are placed 5 cm apart. Find the position of the point at which the resultant electric field is zero:

A pith ball of mass ' $m$ ' gram and charge ' $Q$ ' is suspended using a mass less silk thread near a large charged conducting metal sheet of area ' $A$ ' and surface charged density ' $\sigma$ '. If the silk thread makes an angle $\Theta$ ...

Uniform electric field of $5 \times 10^3 \mathrm{NC}^{-1}$ is maintained in the positive Y direction. Now a point charge of $2 \times 10^{-4} \mathrm{C}$ at rest is released from the origin. The kinetic energy attained by the charge when it...

In a uniform electric field $10^6 N C^{-1}$ an electric dipole of length 4 cm is placed with its axis making an angle $60^{\circ}$ with the electric field. If the dipole experiences a torque of $8 \sqrt{3} \mathrm{~N} \mathrm{~m}$.
Find the...

Bodies $P, Q, R, S$ are labelled as having charges $Q_P=0.5 \times 10^{-19} C, Q_Q=0.7 \times 10^{-19} C$, $Q_R=2.1 \times 10^{-19} C, Q_S=4.8 \times 10^{-19} C$ respectively.
Select the body having the correct charge.
[Given electronic cha...

A charge of $5 \mu \mathrm{C}$ is placed at the centre of a spherical shell $S_1$ of radius 10 cm . Now this system is enclosed inside another spherical shell $S_2$ of radius 20 cm . The ratio of the electrical flux through the surface $S_2...

Calculate the vapour pressure that can help the formation of a spherical droplet of water of radius $6.25 \times 10^{-5} \mathrm{~m}$ at $22^{\circ} \mathrm{C}$. Given: The surface tension of water at the given temperature is $7.28 \times 1...

Two neutral bodies of masses $m_1$ and $m_2$ are kept at a distance of $r \mathrm{~cm}$ from one another in a vacuum medium. A gravitational force Fracts between the two bodies. The entire set-up is then transferred, as it is, to a water me...

Two particles, one heavy and the other light, placed at 50 cm from each other, are under the influence of gravitational force of one another. If mass of the heavier particle is 4 kg and its acceleration under the influence of gravitational ...

A vessel of volume $27 \times 10^4 \mathrm{cc}$, contains a mixture of Hydrogen (molar mass $=2 \mathrm{~g} \mathrm{~mol}^{-1}$ ) and oxygen (molar mass $=32 \mathrm{~g} \mathrm{~mol}^{-1}$ ) gas at standard temperature and pressure. If the...

Find the mass of oxygen gas with which $1.882 \times 10^{23}$ degrees of freedom are associated at N.T.P. Given: Molar mass of diatomic gas, oxygen is $32 \mathrm{~g} \mathrm{~mol}^{-1}$ and oxygen molecule possess three translational and t...

A block of a certain material is heated to a temperature of $500^{\circ} \mathrm{C}$ and then placed on a large ice block. If 1.455 kg of ice melts, find the mass of the block.
Specific heat of the material is $0.39 \mathrm{Jg}^{-1} \mathrm...

Following graph shows four different processes, adiabatic, isothermal, isobaric and isochoric for an ideal gas, from the same initial state. Study the graph carefully and state which of the following statements is correct?

A block of metal, of 25 g mass moves down without acceleration when the plane is inclined at an angle of $30^{\circ}$. When the inclination is increased by $30^{\circ}$, find the downward acceleration of the block.

On both sides of a magnetic needle, two short magnets A and B are placed on the same horizontal line which is perpendicular to the magnetic meridian. The south poles of $A$ and $B$ are facing each other, which are 10 cm and 20 cm respective...

The material selected for making a permanent magnet should have:

An object is dropped from a certain point A at a height ' h ' from the ground. During it's journey straight downwards, the object passes points $B$ and $C$ such that the ratio of time taken $t_1$ to cover $A B$ and $t_2$ to cover $B C$ is $...

A boy, standing at a certain height, kicks a football horizontally with a velocity of $19.6 \mathrm{~ms}^{-1}$. What will be the ratio of horizontal and vertical components of velocities after $2 s$ ?

A particle moves along a parabolic path $y=9 x^2$ in such a way that the x component of velocity remains constant. If, the acceleration of the particle is $2 j m s^{-2}$, find the x component of velocity.

A galvanometer of resistance $50 \Omega$ is having 30 divisions and a current sensitivity $10 \mathrm{~mA} /$ div. What should be the shunt resistance so that it can be converted into an ammeter of range 10 A ?

An electric field and magnetic field $1.8 \times 10^4 \mathrm{Vm}^{-1}$ and $6 \times 10^{-3} \mathrm{~T}$ respectively are applied simultaneously on an electron beam such that path of the beam remains undeviated, then the speed of the elec...

The current through the circular coil is halved and the radius of the coil is doubled. If $B_1$ and $B_2$ are respectively the initial and final magnetic field strength, then:

A circular coil of radius $r=10 c m$ having 300 turns carries a current of 2 A . The coil is suspended vertically in a uniform magnetic field of strength 0.7 T . If the plane of the coil makes an angle $30^{\circ}$ with the magnetic field, ...

The critical angle for a typical glass air interface is $42^{\circ}$. If a ray of light falls normally on one of the faces of the prism of angle $45^{\circ}$. The emergent ray will:

The ratio of the angle of deviation produced by a thin prism, when it is placed in air to the angle of deviation produced when it is immersed in water of refractive index $\frac{4}{3}$ is:

The distance between the objective and eye piece of astronomical telescope in normal adjustment is 27 cm and its magnifying power is 8 . What is the focal length of the eye piece?

An object placed 40 cm in front of a thin convex lens is moved to 60 cm from the lens. If the focal length of the lens is 30 cm the ratio of magnification of the image at the initial position to the final position is:

A singer, during his performance, stands on the edge of a circular turntable, and begins to walk along its edge with a speed of $1.5 \mathrm{~ms}^{-1}$ relative to the ground. The turn table is mounted on a frictionless vertical axle. Its r...

A bullet, fired into a door gets embedded exactly at it's centre, causing the door to rotate about it's vertical axis, practically without friction, with an angular velocity of $0.625 \mathrm{rads}^{-1}$. The door is 1.0 m wide and weighs 1...

Pick out the correct statement from the following;

What is the minimum wavelength of radiation required to detect a p-n junction diode made of a semiconductor having band gap 3.3 eV .
[Planck's constant $h=6.6 \times 10^{34} \mathrm{~J} . \mathrm{s}$ ]