List of top Physics Questions asked in JEE Main

The mean free path of molecules of a certain gas at STP is 1500d, where d is the diameter of the gas molecules. While maintaining the standard pressure, the mean free path of the molecules at 373K is approximately

A planet has double the mass of the earth. Its average density is equal to that of the earth. An object weighing W on earth will weigh on that planet:

An infinitely-long conductor has a current of 14A flowing as shown in the figure. Find the magnetic field at center C.

If half life for a radioactive decay reaction is T. Find the time after which \(\frac{7}{8}th\) of initial mass decays
When electric field is applied to the electrons in a conductor it starts
Wire A and B have their Young’s moduli in the ratio 1:3, area of cross section in the ratio of 1:2 and lengths in ratio of 3:4. If same force is applied on the two wires to elongate then ratio of elongation is equal to
A particle of mass m moving with a velocity v collides with a particle of mass 2m at rest and sticks to it. Velocity of the combined mass equal to? 
Electric potential at a point \( P \) due to a point charge of \( 5 \times 10^{-9} \, \text{C} \) is \( 50 \, \text{V} \). The distance of \( P \) from the point charge is:
An object moves x distance with speed \(v_1\) and next \(x\) distance with speed \(v_2\). The average velocity \(v\) is related to \(v_1\) and \(v_2\) as
Find the radius of the orbit corresponding to the 4th excited state in Li++. (a0 is the radius of first orbit in H-atom)

Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R Assertion (A): Earth has atmosphere and moon doesn’t Reason (R): escape speed on moon is less than that Earth. In the light of the above statements, choose the correct answer from the options given below

Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R. 
Assertion (A): Range of a horizontal projectile is maximum when angle of projection is \(θ = 45°\).
Reason (R): Range is maximum when \(sin\ (2θ)=1\).
In the light of the above statements, choose the correct answer from the options given below

Two projectiles

Two projectiles A and B are projected from the same point on ground with same speed of projection as shown. Find the ratio of maximum height attained by A to that of B.

Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R Assertion (A): Acceleration due to gravity is minimum at equator. Reason (R): Rotation of earth influences acceleration. In the light of the above statements, choose the correct answer from the options given below

A source of sound is moving away from a stationary observer with constant velocity 40 m/s. Find frequency heard by observer, if original frequency of source is 400 Hz and speed of sound in air is 360 m/s

A certain amount of gas of volume $V$ at $27^{\circ} C$ temperature and pressure $2 \times 10^7 Nm ^{-2}$ expands isothermally until its volume gets doubled Later it expands adiabatically until its volume gets redoubled The final pressure of the gas will be (Use $\gamma=15$ )
The following statements are given : 
(1) The average kinetic energy of a gas molecule decreases when the temperature is reduced 
(2) The average kinetic energy of a gas molecule increases with increase in pressure at constant temperature 
(3) The average kinetic energy of a gas molecule decreases with increases in volume 
(4) Pressure of a gas increases with increase in temperature at constant pressure 
(5) The volume of gas decreases with increase in temperature 
Choose the correct answer from the options given below :
In figure $(A)$, mass ' $2\, m$ ' is fixed on mass ' $m$ ' which is attached to two springs of spring constant $k$ In figure $(B)$, mass ' $m$ ' is attached to two spring of spring constant ' $k$ ' and ' $2\, k$ ' If mass ' $m$ ' in $(A)$ and $(B)$ are displaced by distance ' $x$ ' horizontally and then released, then time period $T_1$ and $T_2$ corresponding to (A) and (B) respectively follow the relation
A condenser of $2 \,\mu F$ capacitance is charged steadily from $0$ to $5 C$ Which of the following graph represents correctly the variation of potential difference $(V)$ across it's plates with respect to the charge $( Q )$ on the condenser?
Two charged particles, having same kinetic energy, are allowed to pass through a uniform magnetic field perpendicular to the direction of motion If the ratio of radii of their circular paths is $6: 5$ and their respective masses ratio is $9: 4$ Then, the ratio of their charges will be :
To increase the resonant frequency in seriesLCR circuit,
A small square loop of wire of side $l$ is placed inside a large square loop of wire $L ( L >>l)$ Both loops are coplanar and their centers coincide at point $O$ as shown in figure The mutual inductance of the system is :
The rms value of conduction current in a parallel plate capacitor is $69\, \mu A$ The capacity of this capacitor, if it is connected to $230 \, V$ ac supply with an angular frequency of $600\, rad / s$, will be :
Time taken by light to travel in two different materials $A$ and $B$ of refractive indices $\mu_{ A }$ and $\mu_{ B }$ of same thickness is $t _1$ and $t _2$ respectively If $t_2-t_1=5 \times 10^{-10} s$ and the ratio of $\mu_{ A }$ to $\mu_{ B }$ is $1: 2$ Then the thickness of material, in meter is: (Given $v_A$ and $v_B$ are velocities of light in $A$ and $B$ materials respectively)
A metal exposed to light of wavelength $800\, nm$ and emits photoelectrons with a certain kinetic energy The maximum kinetic energy of photo-electron doubles when light of wavelength $500\, nm$ is used The work function of the metal is (Take $hc =1230 \,eV - nm )$