List of top Physics Questions asked in JEE Main

Consider an electrical circuit containing a two way switch 'S'. Initially S is open and then $T_1$ is connected to $T_2$. As the current in R = 6 $\Omega$ attains a maximum value of steady state level, $T_1$ is disconnected from $T_2$ and immediately connected to $T_3$. Potential drop across r = 3 $\Omega$ resistor immediately after $T_1$ is connected to $T_3$ is _________ V. (Round off to the Nearest Integer) 

 

A coil of inductance 2 H having negligible resistance is connected to a source of supply whose voltage is given by V = 3t volt. (where t is in second). If the voltage is applied when t=0, then the energy stored in the coil after 4 s is _________ J.
The same size images are formed by a convex lens when the object is placed at 20 cm or at 10 cm from the lens. The focal length of convex lens is _________ cm.
The focal length $f$ is related to the radius of curvature $r$ of the spherical convex mirror by :
A common transistor radio set requires 12 V (D.C.). The D.C. source is constructed using a transformer and a rectifier circuit operated at 220 V (A.C.). The number of turns of secondary coil are 24, then the number of turns of primary are _________. (Assume ideal transformer)

Three rays (R, G, B) are incident on PQ... Refractive indices are 1.27, 1.42 and 1.49. The colour of the ray(s) emerging out of the face PR is: 

The time taken for the magnetic energy to reach 25% of its maximum value in an LR circuit is:

The expected graphical representation of the variation of angle of deviation '$\delta$' with angle of incidence 'i' in a prism is : 

In the given figure the magnetic flux through the loop increases according to the relation $\phi_B(t) = 10t^2 + 20t$, where $\phi_B$ is in milliwebers and t is in seconds. The magnitude of current through R=2.0 $\Omega$ resistor at t=5 s is ________ mA. 

 

A ray of laser of a wavelength 630 nm is incident at an angle of $30^\circ$ at the diamond-air interface. It is going from diamond to air. The refractive index of diamond is 2.42 and that of air is 1. Choose the correct option.
An inductor of 10 mH is connected to a 20 V battery through a resistor of 10 k$\Omega$ and a switch. After a long time, when maximum current is set up in the circuit, the current is switched off. The current in the circuit after 1 $\mu$s is $\frac{x}{100}$ mA. Then $x$ is equal to ________. (Take $e^{-1} = 0.37$)
A circular conducting coil of radius 1 m is being heated by the change of magnetic field $\vec{B}$ passing perpendicular to the plane in which the coil is laid. The resistance of the coil is 2 $\mu\Omega$. The magnetic field is slowly switched off such that its magnitude changes in time as \[ B = \frac{4}{\pi} \times 10^{-3} \text{T} \left( 1 - \frac{t}{100} \right) \] The energy dissipated by the coil before the magnetic field is switched off completely is E = ________ mJ.
Your friend is having eye sight problem. She is not able to see clearly a distant uniform window mesh and it appears to her as non-uniform and distorted. The doctor diagnosed the problem as :
For an adiabatic expansion of an ideal gas, the fractional change in its pressure is equal to (where \(\gamma\) is the ratio of specific heats):
A reversible heat engine converts one-fourth of the heat input into work. When the temperature of the sink is reduced by 52 K, its efficiency is doubled. The temperature in Kelvin of the source will be ________ .
The height of victoria falls is 63 m. What is the difference in temperature of water at the top and at the bottom of fall?
[Given 1 cal = 4.2 J and specific heat of water = 1 cal g\(^{-1}\) \(^{\circ}\)C\(^{-1}\)]
A reversible engine has an efficiency of \(\frac{1}{4}\). If the temperature of the sink is reduced by \(58^\circ\text{C}\), its efficiency becomes double. Calculate the temperature of the sink :
A sample of gas with $\gamma = 1.5$ is taken through an adiabatic process in which the volume is compressed from 1200 $cm^3$ to 300 $cm^3$. If the initial pressure is 200 kPa. The absolute value of the workdone by the gas in the process = ________ J.
A heat engine operates between a cold reservoir at temperature T\(_2\) = 400 K and a hot reservoir at temperature T\(_1\). It takes 300 J of heat from the hot reservoir and delivers 240 J of heat to the cold reservoir in a cycle. The minimum temperature of the hot reservoir has to be _________ K.

A perfect gas undergoes a cyclic process ABCA. A→B: Isothermal expansion ($V_1 \to 2V_1$). B→C: Isobaric compression to $V_1$. C→A: Isochoric change to $P_1$. Total work done is :

An electric appliance supplies 6000 J/min heat to the system. If the system delivers a power of 90 W. How long it would take to increase the internal energy by $2.5 \times 10^3$ J ?
One mole of an ideal gas is taken through an adiabatic process where the temperature rises from $27^\circ\text{C}$ to $37^\circ\text{C}$. If the ideal gas is composed of polyatomic molecule that has 4 vibrational modes, which of the following is true?
[R = 8.314 J mol$^{-1}$ K$^{-1}$]
An ideal gas in a cylinder is separated by a piston in such a way that the entropy of one part is \(S_1\) and that of the other part is \(S_2\). Given that \(S_1>S_2\). If the piston is removed then the total entropy of the system will be:
Match List I with List II.
List I: (a) Isothermal (b) Isochoric (c) Adiabatic (d) Isobaric.
List II: (i) Pressure constant (ii) Temperature constant (iii) Volume constant (iv) Heat content constant.
A refrigerator consumes an average 35 W power to operate between temperature -10\(^{\circ}\)C to 25\(^{\circ}\)C. If there is no loss of energy then how much average heat per second does it transfer ?