List of top Questions asked in JEE Main

A bar magnet is released from rest along the axis of a very long, vertical aluminum tube. After sometime the magnet will :

an body cools down from 80°C to 60°C in 5 minutes The temperature pf the surrounding is 20°C. The time taken to cool from 60°C to 40°C is

The temperature of an ideal gas is increased from 200 K to 800 K. If r.m.s. speed of gas at 200K is v0. Then, r.m.s. speed of the gas at 800 K will be

The amplitude of 15sin(1000πt) is modulated by 10sin(4πt) signal. The amplitude modulated signal contains frequency(ies) of
(A) 500 Hz 
(B) 2 Hz  
(C) 250 Hz  
(D) 498 Hz  
(E) 502 Hz 
Choose the correct answer from the options given below: 

A point charge \(2×10^{−2}C\) is moved from P to S in a uniform electric field of \(30NC^{−1}\) directed along positive x-axis. If coordinates of P and S are \((1,2,0) m \) and \((0,0,0) m\) respectively, the work done by electric field will be

A gas mixture consists of 2 moles of oxygen and 4 moles of neon at temperature T. Neglecting all vibrational modes, the total internal energy of the system will be,

Given below are two statement : one is labelled as Assertion A and the other is labelled as Reason R.  
Assertion A : EM waves used for optical communication have longer wavelengths than that of microwave, employed in Radar technology.  
Reason R : Infrared EM waves are more energetic than microwaves, (used in Radar)  
In the light of given statements, choose the correct answer from the options given below:  

Heat energy of 184 kJ is given to ice of mass $600 g$ at −12°C. Specific heat of ice is $ 2222.3 J kg^{−1}C^{−1}$ and latent heat of ice in $ 336 kJkg^{−1} $
A. Final temperature of system will be 0°C.
B. Final temperature of the system will be greater than 0°C.  
C. The final system will have a mixture of ice and water in the ratio of 5:1.  
D. The final system will have a mixture of ice and water in the ratio of 1:5. 
E. The final system will have water only.
Choose the correct answer from the options given below:

Which of the following are true?
A. Speed of light in vacuum is dependent on the direction of propagation. 
B. Speed of light in a medium is independent of the wavelength of light. 
C. The speed of light is independent of the motion of the source. 
D. The speed of light in a medium is independent of intensity.
Choose the correct answer from the options given below:

For a particle performing linear SHM, its position (x) as a function of time (t) is given by x = Asin(ωt + δ). Given that, at t = 0, particle is at +A/2 and is moving towards x = +A. Find δ

Let A=\(\begin{bmatrix} 1 & \frac{1}{51} \\ 0 & 1\end{bmatrix}\). If B=\(\begin{bmatrix} 1 & 2 \\ -1 & -1\end{bmatrix}\)A \(\begin{bmatrix} -1 & -2 \\ 1 & 1\end{bmatrix}\), then the sum of all the elements of the matrix \(\sum^{50}_{n=1}B^n\) is equal to

Assuming the earth to be a sphere of uniform mass density, the weight of a body at a depth \(d=\frac{R}{2}\) from the surface of earth, if its weight on the surface of earth is 200 N, will be 

A radioactive nuclei X decays simultaneously to two nuclei Y and Z as:

t_½ is 12 minutes while t'_½ is 3 minutes. Find the time in which nuclei X decays 50%.

\(tan^{-1}(\frac {1+\sqrt 3}{3+\sqrt 3})+sec^{-1}(\sqrt {\frac {8+4\sqrt 3}{3+3\sqrt 3})}\) is equal to:

Pick the correct graph between potential V at distance r from centre for the uniformly charged spherical shell of radius R.
 

Mass of body = 500 kg,  μ= 0.7. Find work required to move a distance of 4 Km if the body moves with velocity 10 m/s.

Match the physical quantity in column-I with the respective dimension in column-II and choose the correct option.

The length of a conductor having resistance 160 Ω, is compressed to 25% of its initial value. The new resistance will be

Statement I : In LCR circuit, by increasing frequency current increases first then decreases.
Statement II : Power factor of LCR circuit is one.
Choose the correct option.

Assertion (A): An electrical dipole is enclosed in a closed gaussian surface. The total flux through the enclosed surface is zero. 
Reason (R): Net charge inside the enclosed surface is zero.

A circular ring is placed in magnetic field of 0.4 T. Suddenly its radius starts shrinking at the rate of 1 mm/s. Find the induced emf in the ring at r = 2 cm.

Bob P is released from the position of rest at the moment shown. If it collides elastically with an identical bob Q hanging freely then velocity of Q, just after collision is (g = 10 m/s²).

Position-time graph for a particle is parabolic and is as shown:

Choose the corresponding v – t graph.