List of top Physics Questions asked in JEE Main

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 equivalent resistance between the points \(A\) and \(B\) in the given circuit is \[ \frac{x}{5}\,\Omega. \] 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 ________. (\( \mu_0 = 4\pi \times 10^{-7}\,\text{T m A}^{-1} \)) 

A convex lens of refractive index \(1.5\) and focal length \(f=18\) cm is immersed in water. The difference in focal lengths of the given lens when it is in water and in air is \( \alpha \times f \). Find the value of \( \alpha \). (Given: refractive index of water \(=\dfrac{4}{3}\))

The velocity (\(v\)) – distance (\(x\)) graph is shown in the figure. Which graph represents acceleration (\(a\)) versus distance (\(x\)) variation of this system? 

The reading of the ammeter (\(A\)) in steady state in the following circuit (assuming negligible internal resistance of the ammeter) is ________ A.

Three parallel plate capacitors each with area \(A\) and separation \(d\) are filled with two dielectric (\(k_1\) and \(k_2\)) in the following fashion. (\(k_1>k_2\)) Which of the following is true? 

A point source is kept at the center of a spherically enclosed detector. If the volume of the detector is increased by 8 times, the intensity will
A cubical block of density \( \rho_b = 600\,\text{kg/m}^3 \) floats in a liquid of density \( \rho_l = 900\,\text{kg/m}^3 \). If the height of block is \(H = 8.0\,\text{cm}\), then height of the submerged part is ________ cm.
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.
In the Young's double slit experiment the intensity produced by each one of the individual slits is \(I_0\). The distance between two slits is \(2\,\text{mm}\). The distance of screen from slits is \(10\,\text{m}\). The wavelength of light is \(6000\,\text{\AA}\). The intensity of light on the screen in front of one of the slits is ________.
In a vernier callipers, 50 vernier scale divisions are equal to 48 main scale divisions. If one main scale division = 0.05 mm, then the least count of the vernier callipers is ________ mm.
Distance between an object and three times magnified real image is 40 cm. The focal length of the mirror used is ________ cm.
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.

Two identical circular loops \(P\) and \(Q\) each of radius \(r\) are lying in parallel planes such that they have common axis. The current through \(P\) and \(Q\) are \(I\) and \(4I\) respectively in clockwise direction as seen from \(O\). The net magnetic field at \(O\) is: 

The binding energy for the following nuclear reactions are expressed in MeV.
\[ {}^{3}_{2}\text{He} + {}^{1}_{0}\text{n} \rightarrow {}^{4}_{2}\text{He} + 20 \text{ MeV} \] \[ {}^{4}_{2}\text{He} + {}^{1}_{0}\text{n} \rightarrow {}^{5}_{2}\text{He} - 0.9 \text{ MeV} \] If \( X_3, X_4, X_5 \) denote the stability of \( {}^{3}_{2}\text{He}, {}^{4}_{2}\text{He} \) and \( {}^{5}_{2}\text{He} \), respectively, then the correct order is:
In a meter bridge experiment to determine the value of unknown resistance, first the resistances \(2\,\Omega\) and \(3\,\Omega\) are connected in the left and right gaps of the bridge and the null point is obtained at a distance \(l\) cm from the left end. Now, when an unknown resistance \(x\,\Omega\) is connected in parallel to \(3\,\Omega\), the null point is shifted by \(10\,\text{cm}\) to the right. The value of \(x\) is ________ \(\Omega\).

A point charge \(q = 1\,\mu\text{C}\) is located at a distance \(2\,\text{cm}\) from one end of a thin insulating wire of length \(10\,\text{cm}\) having a charge \(Q = 24\,\mu\text{C}\), distributed uniformly along its length, as shown in the figure. Force between \(q\) and wire is ________ N. 

A flexible chain of mass \(m\) hangs between two fixed points at the same level. The inclination of the chain with the horizontal at the two points of support is \(30^\circ\). Considering the equilibrium of each half of the chain, the tension of the chain at the lowest point is ________.
A soap bubble of surface tension \(0.04\,\text{N/m}\) is blown to a diameter of \(7\,\text{cm}\). If \((15000 - x)\,\mu\text{J}\) of work is done in blowing it further to make its diameter \(14\,\text{cm}\) \((\pi = 22/7)\), then the value of \(x\) is ________.
A regular hexagon is formed by six wires each of resistance \( r \,\Omega \) and the corners are joined to the centre by wires of same resistance. If the current enters at one corner and leaves at the opposite corner, the equivalent resistance of the hexagon between the two opposite corners will be

Identify the correct truth table of the given logic circuit. 

The fifth harmonic of a closed organ pipe is found to be in unison with the first harmonic of an open pipe. The ratio of lengths of closed pipe to that of the open pipe is \( \frac{5}{x} \). The value of \( x \) is ________.
A moving coil galvanometer of resistance \(100\,\Omega\) shows a full scale deflection for a current of \(1\,\text{mA}\). The value of resistance required to convert this galvanometer into an ammeter, showing full scale deflection for a current of \(5\,\text{mA}\), is ________ \(\Omega\).
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 ________.