List of top Physics Questions asked in JEE Main

The number of air molecules per cm³ increased from 3 × 10¹⁹ to 12 × 10¹⁹. The ratio of collision frequency of air molecules before and after the increase in the number respectively is :

For designing a voltmeter of range 50 V and an ammeter of range 10 mA using a galvanometer which has a coil of resistance 54Ω showing a full scale deflection for 1 mA as in figure.

(A) for voltmeter R ≈ 50 kΩ
(B) for ammeter r ≈ 0.2Ω
(C) for ammeter r ≈ 6Ω
(D) for voltmeter R ≈ 5 kΩ (E) for voltmeter R ≈ 500Ω
Choose the correct answer from the options given below :

A 12V battery connected to a coil of resistance 6Ω through a switch, drives a constant current in the circuit. The switch is opened in 1ms. The emf induced across the coil is 20V. The inductance of the coil is:

Match the list-I with list-II and choose the correct option.

	List-I		List-II
(A).	Microwave	(P).	1 nm - 400nm
(B).	Ultraviolet	(Q).	1 nm - 1nm
(C).	X-rays	(R).	2.5 µm - 750nm
(D).	Infrared	(S).	1 µm - 1nm

A single slit of width a is illuminated by a monochromatic light of wavelength 600 nm. The value of 'a' for which first minimum appears at θ=30° on the screen will be :

In the given circuit, the current (I) through the battery will be

Height of the receiving and transmitting antenna in communication of a signal are 245 m and 180 m respectively. Find the maximum distance between the two antennas for proper communication.

The position vector of a particle related to time t is given by $\vec{r}=(10t\hat{i}+15t^2\hat{j}+7\hat{k})m$
The direction of net force experienced by the particle is :

By what percentage will the transmission range of a TV tower be affected when the height of the tower is increased by 21% ?

The speed of a wave produced in water is given by v=$λ^ag^bρ^c$. Where λ,g and ρ are wavelength of wave, acceleration due to gravity and density of water respectively. The values of a, b and c respectively, are:

A vector in x-y plane makes an angle of 30º with y-axis. The magnitude of y-component of vector is $2\sqrt3$. The magnitude of x -component of the vector will be :

A body is released from a height equal to the radius (r) of the earth. The velocity of the body when it strikes the surface of the earth will be:

A wire of length 'L' and radius 'r' is clamped rigidly at one end. When the other end of the wire is pulled by a force f, its length increases by 'l'. Another wire of same material of length '2L' and radius '2r' is pulled by a force '2f'. Then the increase in its length will be

For a uniformly charged thin spherical shell, the electric potential (V) radially away from the entre (O) of shell can be graphically represented as –

A thermodynamic system is taken through cyclic process. The total work done in the process is:

A flask contains Hydrogen and Argon in the ratio 2:1 by mass. The temperature of the mixture is 30°C. The ratio of average kinetic energy per molecule of the two gases (K argon/K hydrogen) is:
(Given: Atomic Weight of Ar = 39.9)

In a linear Simple Harmonic Motion (SHM)
(A) Restoring force is directly proportional to the displacement.
(B) The acceleration and displacement are opposite in direction.
(C) The velocity is maximum at mean position.
(D) The acceleration is minimum at extreme points.
Choose the correct answer from the options given below:

A particle is moving with constant speed in a circular path. When the particle turns by an angle $90\degree$ , the ratio of instantaneous velocity to its average velocity is $π : x\sqrt2$. The value of x will be -

A capacitor of capacitance 900 μF is charged by a 100 V battery. The capacitor is disconnected from the battery and connected to another uncharged identical capacitor such that one plate of the uncharged capacitor is connected to the positive plate and another plate of the uncharged capacitor is connected to the negative plate of the charged capacitor. The loss of energy in this process is measured as $x \times 10^{-2}$ J. The value of $x$ is:

In the figure given below, a block of mass $M=490 g$ placed on a frictionless table is connected with two springs having same spring constant $\left( K =2 N m ^{-1}\right)$ If the block is horizontally displaced through ' $X$ ' $m$ then the number of complete oscillations it will make in $14 \pi$ seconds will be

The speed of a swimmer is $4 km h ^{-1}$ in still water If the swimmer makes his strokes normal to the flow of river of width $1 km$, he reaches a point $750 m$ down the stream on the opposite bank.The speed of the river water is ___ $km h ^{-1}$

A small block of mass 100 g is tied to a spring of spring constant 7.5 N/m and length 20 cm. The other end of spring is fixed at a particular point A. If the block moves in a circular path on a smooth horizontal surface with constant angular velocity 5 rad/s about point A, then tension in the spring is-

Two identical cells, when connected either in parallel or in series gives same current in an external resistance $5 \Omega$ The internal resistance of each cell will be__ $\Omega$

A source supplies heat to a system at the rate of 1000 W. If the system performs work at a rate of 200 W. The rate at which internal energy of the system increase is

A thin rod having a length of $1 m$ and area of cross-section $3 \times 10^{-6} m ^2$ is suspended vertically from one end. The rod is cooled from $210^{\circ} C$ to $160^{\circ} C$ After cooling, a mass $M$ is attached at the lower end of the rod such that the length of rod again becomes $1m$. Young's modulus and coefficient of linear expansion of the rod are $2 \times 10^{11} N m ^{-2}$ and $2 \times 10^{-5} K ^{-1}$, respectively. The value of $M$ is ____ $kg$. (Take $g =10 \ m s ^{-2}$)