List of top Physics Questions asked in JEE Main

A particle of mass $m$ falls from rest through a resistive medium having resistive force $F=-kv$, where $v$ is the velocity of the particle and $k$ is a constant. Which of the following graphs represents velocity $v$ versus time $t$?

Assuming in forward bias condition there is a voltage drop of $0.7$ V across a silicon diode, the current through diode $D_1$ in the circuit shown is ________ mA. (Assume all diodes in the given circuit are identical)

Two wires $A$ and $B$ made of different materials have lengths $6.0$ cm and $5.4$ cm, and areas of cross-sections $3.0\times10^{-5}\,\text{m}^2$ and $4.5\times10^{-5}\,\text{m}^2$, respectively. They are stretched by the same magnitude under the same load. If the ratio of Young’s modulus of $A$ to that of $B$ is $x:3$, find the value of $x$.

Three long straight wires carrying current are arranged mutually parallel as shown in the figure. The force experienced by $15$ cm length of wire $Q$ is ________. ($ \mu_0 = 4\pi \times 10^{-7}\,\text{T m A}^{-1} $)

The electric field of an electromagnetic wave travelling through a medium is given by \[ \vec{E}(x,t)=25\sin(2\times10^{15}t-10^{7}x)\,\hat{n}. \] Then the refractive index of the medium is ________. (All given measurements are in SI units)

Water drops fall from a tap on the floor, $5$ m below, at regular intervals of time. The first drop strikes the floor when the sixth drop begins to fall. The height at which the fourth drop will be from the ground, at the instant when the first drop strikes the ground, is ________ m. ($ g = 10 \, \text{m s}^{-2} $)

In the potentiometer, when the cell in the secondary circuit is shunted with $4\,\Omega$ resistance, the balance is obtained at a length $120$ cm of wire. Now when the same cell is shunted with $12\,\Omega$ resistance, the balance is shifted to a length of $180$ cm. The internal resistance of the cell is ________ $ \Omega $.

When both jaws of a vernier calipers touch each other, zero mark of the vernier scale is right to the zero mark of main scale. 4th mark on vernier scale coincides with a certain mark on the main scale. While measuring the length of a cylinder, observer observes 15 divisions on main scale and 5th division of vernier scale coincides with a main scale division. Measured length of cylinder is ________ mm. (Least count of Vernier calliper = $0.1$ mm)

Given below are two statements: Statement I: A plane wave after passing through a prism remains a plane wave, but passing through a small pin hole may become a spherical wave. Statement II: The curvature of a spherical wave emerging from a slit will increase for increasing slit width. In the light of the above statements, choose the correct answer:

The magnitudes of power of a biconvex lens (refractive index $1.5$) and that of a plano-convex lens (refractive index $1.7$) are same. If the curvature of the plano-convex lens exactly matches with the curvature of the back surface of the biconvex lens, then the ratio of radii of curvature of the front and back surfaces of the biconvex lens is:

The electric current in the circuit is given as \[ i=i_0\left(\frac{t}{T}\right). \] The r.m.s. current for the period $ t=0 $ to $ t=T $ is:

After release, the blocks moves 81 cm in 9 seconds. Find moment of inertia of the pulley :
(Given $m_{1} = 400$ gm, $m_{2} = 350$ gm, R = 2 cm, g = 10 m/s$^2$)

Density of water at 4$^\circ$C is 1000 kg/m$^3$ and at 20$^\circ$C it is 998 kg/m$^3$. If 4kg of water is heated from 4$^\circ$C to 20$^\circ$C, the change in internal energy of water is : (Given : specific heat capacity of water = 4200 J/kg K, Atmospheric pressure P = $10^5$ Pa).

The ratio of de Broglie wavelength of a deuteron with kinetic energy $E$ to that of an alpha particle with kinetic energy $2E$ is $n:1$. (Assume mass of proton $=$ mass of neutron.) Find the value of $n$.

A simple pendulum of string length 30 cm performs 20 oscillations in 10 s. The length of the string required for the pendulum to perform 40 oscillations in the same time duration is_______ cm. [Assume that the mass of the pendulum remains same]}

Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Consider a ferromagnetic material :
Assertion (A): The individual atoms in a ferromagnetic material possess a magnetic dipole moment and interact with one another in such a way that they spontaneously align themselves forming domains.
Reason (R): At high enough temperature, the domain structure of ferromagnetic material disintegrates. Thus, magnetization will disappear at high enough temperature known as Curie temperature.
In the light of the above statements, choose the correct answer from the options given below :

Match List-I with List-II.

Choose the correct answer from the options given below :}

In a screw gauge, the zero of the circular scale lies 3 divisions above the horizontal pitch line when their metallic studs are brought in contact. Using this instrument thickness of a sheet is measured. If pitch scale reading is 1 mm and the circular scale reading is 51 then the correct thickness of the sheet is_______ mm. [Assume least count is 0.01 mm]}

A simple pendulum made of mass 10 g and a metallic wire of length 10 cm is suspended vertically in a uniform magnetic field of 2 T. The magnetic field direction is perpendicular to the plane of oscillations of the pendulum. If the pendulum is released from an angle of 60° with vertical, then maximum induced EMF between the point of suspension and point of oscillation is_______ mV. (Take g = 10 m/s²)}

Using a variable frequency ac voltage source the maximum current measured in the given LCR circuit is 50 mA for V = 5 sin (100t) The values of L and R are shown in the figure. The capacitance of the capacitor (C) used is_______ µF.

The space between the plates of a parallel plate capacitor of capacitance C (without any dielectric) is now filled with three dielectric slabs of dielectric constants $k_1 = 2$, $k_2 = 3$ and $k_3 = 3$ (as shown in figure). If new capacitance is n/3 C then the value of n is_______.

The equation of the electric field of an electromagnetic wave propagating through free space is given by: $E = \sqrt{377} \sin(6.27 \times 10^3 t - 2.09 \times 10^{-5} x)$ N/C. The average power of the electromagnetic wave is (1/a) W/m². The value of a is_______. (Take $\sqrt{\mu_0/\varepsilon_0} = 377$ in SI units)}

A boy throws a ball into air at $45^\circ$ from the horizontal to land it on a roof of a building of height $H$. If the ball attains maximum height in $2\,\text{s}$ and lands on the building in $3\,\text{s}$ after launch, then the value of $H$ is ___ m.
(Given: $g = 10\,\text{m s}^{-2}$)

There are three co-centric conducting spherical shells $A$, $B$ and $C$ of radii $a$, $b$ and $c$ respectively $(c>b>a)$ and they are charged with charges $q_1$, $q_2$ and $q_3$ respectively. The potentials of the spheres $A$, $B$ and $C$ respectively are:

For the series LCR circuit connected with $220\,\text{V},\,50\,\text{Hz}$ a.c. source as shown in the figure, the power factor is $\dfrac{\alpha}{10}$. The value of $\alpha$ is ___.