List of top Physics Questions asked in JEE Main

In a microscope of tube length $10\,\text{cm}$ two convex lenses are arranged with focal lengths $2\,\text{cm}$ and $5\,\text{cm}$. Total magnification obtained with this system for normal adjustment is $(5)^k$. The value of $k$ is ___.

Three charges $+2q$, $+3q$ and $-4q$ are situated at $(0,-3a)$, $(2a,0)$ and $(-2a,0)$ respectively in the $x$-$y$ plane. The resultant dipole moment about origin is ___.

10 mole of an ideal gas is undergoing the process shown in the figure. The heat involved in the process from $ P_1 $ to $ P_2 $ is $ \alpha $ Joule $(P_1 = 21.7 \text{ Pa}, P_2 = 30 \text{ Pa}, C_v = 21 \text{ J/K mol}, R = 8.3 \text{ J/mol K})$. The value of $ \alpha $ is ________.

The displacement of a particle executing simple harmonic motion with time period $T$ is expressed as \[ x(t)=A\sin\omega t, \] where $A$ is the amplitude of oscillation. If the maximum value of the potential energy of the oscillator is found at \[ t=\frac{T}{2\beta}, \] then the value of $\beta$ is ________.

In the given figure, the blocks $A$, $B$ and $C$ weigh $4\,\text{kg}$, $6\,\text{kg}$ and $8\,\text{kg}$ respectively. The coefficient of sliding friction between any two surfaces is $0.5$. The force $\vec{F}$ required to slide the block $C$ with constant speed is ___ N.
(Given: $g = 10\,\text{m s}^{-2}$)

Two circular discs of radius $10$ cm each are joined at their centres by a rod, as shown in the figure. The length of the rod is $30$ cm and its mass is $600$ g. The mass of each disc is also $600$ g. If the applied torque between the two discs is $43\times10^{-7}$ dyne·cm, then the angular acceleration of the system about the given axis $AB$ is ________ rad s$^{-2}$.

For two identical cells each having emf $E$ and internal resistance $r$, the current through an external resistor of $6\,\Omega$ is the same when the cells are connected in series as well as in parallel. The value of the internal resistance $r$ is ________ $\Omega$.

The moment of inertia of a square loop made of four uniform solid cylinders, each having radius R and length L ($R \le L$) about an axis passing through the mid points of opposite sides, is (Take the mass of the entire loop as M) :

Which of the following best represents the temperature versus heat supplied graph for water, in the range of $-20^\circ\text{C}$ to $120^\circ\text{C}$?

When a part of a straight capillary tube is placed vertically in a liquid, the liquid rises upto certain height $ h $. If the inner radius of the capillary tube, density of the liquid and surface tension of the liquid decrease by $1%$ each, then the height of the liquid in the tube will change by ________ %.

A gas of certain mass filled in a closed cylinder at a pressure of $3.23\,\text{kPa}$ has temperature $50^\circ$C. The gas is now heated to double its temperature. The modified pressure is ___ Pa.

When a light of a given wavelength falls on a metallic surface the stopping potential for photoelectrons is $3.2\ \text{V}$. If a second light having wavelength twice of the first light is used, the stopping potential drops to $0.7\ \text{V}$. The wavelength of the first light is ________ m.

An infinitely long straight wire carrying current $I$ is bent in a planar shape as shown in the diagram. The radius of the circular part is $r$. The magnetic field at the centre $O$ of the circular loop is :

In an experiment, a set of readings are obtained as follows: \[ 1.24~\text{mm},\ 1.25~\text{mm},\ 1.23~\text{mm},\ 1.21~\text{mm}. \] The expected least count of the instrument used in recording these readings is _______ mm.

Two point charges of $1\,\text{nC}$ and $2\,\text{nC}$ are placed at two corners of an equilateral triangle of side $3$ cm. The work done in bringing a charge of $3\,\text{nC}$ from infinity to the third corner of the triangle is ________ $\mu\text{J}$. \[ \left(\frac{1}{4\pi\varepsilon_0}=9\times10^9\,\text{N m}^2\text{C}^{-2}\right) \]

The equivalent resistance between the points $A$ and $B$ in the given circuit is \[ \frac{x}{5}\,\Omega. \] Find the value of $x$.

Consider light travelling from a medium A to medium B separated by a plane interface. If the light undergoes total internal reflection during its travel from medium A to B and the speed of light in media A and B are $2.4 \times 10^8$ m/s and $2.7 \times 10^8$ m/s, respectively, then the value of critical angle is :

In the following $p\text{–}V$ diagram, the equation of state along the curved path is given by \[ (V-2)^2 = 4ap, \] where $a$ is a constant. The total work done in the closed path is:

A voltage regulating circuit consisting of a Zener diode having breakdown voltage of $10\,\text{V}$ and maximum power dissipation of $0.4\,\text{W}$ is operated at $15\,\text{V}$. The approximate value of protective resistance in this circuit is ___ $\Omega$.

A thin convex lens of focal length $ 5 $ cm and a thin concave lens of focal length $ 4 $ cm are combined together (without any gap), and this combination has magnification $ m_1 $ when an object is placed $ 10 $ cm before the convex lens.

Keeping the positions of the convex lens and the object undisturbed, a gap of $ 1 $ cm is introduced between the lenses by moving the concave lens away. This leads to a change in magnification of the total lens system to $ m_2 $.

The value of $ \dfrac{m_1}{m_2} $ is

Two blocks with masses 100 g and 200 g are attached to the ends of springs A and B as shown in figure. The energy stored in A is E. The energy stored in B, when spring constants $k_A, k_B$ of A and B, respectively satisfy the relation $4k_A = 3k_B$, is :

A light wave described by E = 60[$\sin(3 \times 10^{15})t + \sin(12 \times 10^{15})t$] (in SI units) falls on a metal surface of work function 2.8 eV. The maximum kinetic energy of ejected photoelectron is (approximately)________ eV. (h=$6.6 \times 10^{-34}$ J.s. and e=$1.6 \times 10^{-19}$ C)

Five persons $P_1, P_2, P_3, P_4$ and $P_5$ recorded object distance ($u$) and image distance ($v$) using same convex lens having power $+5$ D as (25,96), (30,62), (35,37), (45,35) and (50,32) respectively. Identify correct statement.

A parallel beam of light travelling in air (refractive index $1.0$) is incident on a convex spherical glass surface of radius of curvature $50 \, \text{cm}$. Refractive index of glass is $1.5$. The rays converge to a point at a distance $x \, \text{cm}$ from the centre of curvature of the spherical surface. The value of $x$ is ___________.

When 300 J of heat is given to an ideal gas with $ C_p = \frac{7}{2}R $, its temperature rises from 20°C to 50°C keeping its volume constant. The mass of the gas is (approximately) ______ g. (R = 8.314 J/mol K)