COMEDK 2025 Evening Shift

Three charges, $Q,-q$ and $2 q$ are placed at the vertices of a right-angled isosceles triangle. What is the value of $q$ for the net electrostatic energy of the configuration to be zero?

In to a vessel containing pure water a clean glass tube of radius $3.6 \times 10^{-4} \mathrm{~m}$ is held vertically with 12 cm of the tube above the water level. Now the capillary tube is moved down in to the water so that only 2 cm of it...

The unit of universal gravitational constant is :

If the distance between the Sun and Earth is doubled, then the duration of the year on earth will be :
[Given actual duration of the year $=\mathbf{T}$ ]

The rate of heat conduction in the given two metal rods having the same length is found to be the same when the temperature difference between the ends is kept $30^{\circ} \mathrm{C}$ If the area of cross section of the first rod is $8 \tim...

The total number of degrees of freedom associated with $2 \mathrm{~cm}^3$ of Nitrogen gas at normal temperature and pressure is:
[Given Avogadro number as ' N ' ]

The rms velocity of the gas molecule at $327^{\circ} \mathrm{C}$ is same as the rms velocity of the oxygen molecules at $27^{\circ} \mathrm{C}$. If the molecular weight of oxygen is 32 then the molecular weight of the given gas molecule is:

A given volume of gas at NTP is allowed to expand 6 times of its original volume, first under isothermal condition and then under adiabatic condition. Which of the given statement is correct? [Given $\frac{c_p}{c_v}=\gamma=1.4$ ]

A body of mass 10 kg is moving up on an inclined plane of $30^{\circ}$ with an acceleration $2 \mathrm{~ms}^{-2}$. Find the force required, if the coefficient of friction between the object and the plane surface is $\frac{\sqrt{3}}{6}$, [gi...

A metal rod of susceptibility 799 is subjected to a magnetising field of $2000 \mathrm{Am}^{-1}$. The permeability of the material of the rod is: (Given $\mu_0=4 \pi \times 10^{-7} \mathrm{TmA}^{-1}$ )

A short bar magnet placed with its axis at $45^{\circ}$ with an external field of $400 \times 10^{-4} \mathrm{~T}$ experiences a torque of 0.024 Nm . If a solenoid of cross-sectional area $10^{-4} \mathrm{~m}^2$ and 500 turns replaces the s...

A boy is running along a straight horizontal road with a constant speed $5 \mathrm{~ms}^{-1}$. While running he throws a stone with a velocity $30 \mathrm{~ms}^{-1}$ at an angle $60^{\circ}$ with the horizontal. Then the time of flight of t...

Select the graph which represents the motion of a particle along a straight line with uniform acceleration.

A straight wire of mass 250 g and length 2.5 m carries a current of 4 A . It can be suspended in mid air by a uniform horizontal magnetic field of magnitude:

In a particular case X , a certain length of insulated copper wire is bent to form double loops of equal radii. In another case Y the same copper wire is bent to form three loops of equal radii. If the same steady current is passed through ...

A current carrying closed loop in the form of a right isosceles triangle XYZ is placed in a uniform magnetic field $B$ acting along $X Y$ of the loop. If the magnetic force on the arm $Y Z$ is $\sqrt{2} F$, then the force on the arm $X Z$ i...

A beam of incident parallel light falls on a diverging lens of focal length 20 cm in magnitude. If a converging lens of focal length 15 cm in magnitude is placed at a distance of 10 cm to the right of the diverging lens on the other side, t...

In the normal adjustment of an astronomical telescope, the objective and eyepiece are 36 cm apart. If the magnifying power of the telescope is 8 , find the focal lengths of the objective and eyepiece.

An object of height $h$ is placed midway between $f$ and $2 f$ in front of a biconvex lens. A real inverted image is captured on a screen placed a little beyond 2 f on the other side of the lens. If the whole arrangement is immersed in wate...

A plano-convex lens made of refractive index 1.5 and having radius of curvature $\mathrm{R}=4 \mathrm{~cm}$ fits exactly into a planoconcave lens made of refractive index 1.3 and having the same radius of curvature $R=4 \mathrm{~cm}$ such t...

Applying a constant torque the speed of a flywheel is increased from 1800 rpm to 2400 rpm in 10 seconds. The number of revolutions made by the flywheel during this time is:

What is the dc component of the output voltage if a sinusoidal signal of 33 V peak voltage is the input of a half wave diode rectifier circuit?

An intrinsic semiconductor has equal concentrations of hole and electron which is equal to $4 \times 10^8 \mathrm{~m}^{-3}$. During its conversion to extrinsic semiconductor, concentration of hole increases to $8 \times 10^{10} \mathrm{~m}^...

The zener voltage in the circuit shown is $\mathrm{V}_{\mathrm{Z}}=20 \mathrm{~V}$. The load resistance $\mathrm{R}_{\mathrm{L}}=5 \mathrm{k} \Omega$ and the resistance $\mathrm{R}_{\mathrm{S}}=10 \mathrm{k} \Omega$. If the input voltage is...

Two physical quantities having the same dimensional formula $\left[\mathrm{M}^1 \mathrm{~L}^{-1} \mathrm{~T}^{-2}\right]$ are

Young's double slit experiment is first done in air and then in a medium of refractive index $\mu$. If the 7 th dark fringe in the medium lies where the 4 th bright fringe is in air, then the value of $\mu$ is :

The interference pattern is obtained with two coherent light sources of intensity ratio $9: 1$.
The ratio of $\frac{I_{\operatorname{MAX}}+I_{\operatorname{MIN}}}{I_{\operatorname{MAX}}-I_{\operatorname{MIN}}}$ is $\frac{\alpha}{\beta}$. Th...

The wavelength of a monochromatic light which is used in single slit diffraction is 800 nm . The width of the single slit for which the first minimum appears at $\theta=45^{\circ}$ on the screen will be:

The fundamental frequency of sound produced in an open pipe of length $\mathbf{L}_1$ is same as the frequency of the $3^{\text {rd }}$ harmonic of the sound produced in the closed pipe of length $\mathbf{L}_2$ Then the ratio of $\frac{L_1}{...

Momentum of a body is increased to three times its original value. By what percentage will its kinetic energy change?