List of top Physics Questions asked in JEE Main

Two identical thin biconvex lenses of focal length 15 cm and refractive index 1.5 are in contact with each other. The space between the lenses is filled with a liquid of refractive index 1.25. The focal length of the combination is ___ cm.

As shown in the figure an inductor of inductance 200 mH is connected to an AC source of emf 220 V and frequency 50 Hz. The instantaneous voltage of the source is 0 V when the peak value of current is$\sqrt{\frac{a}{\pi}}$.The value of a is ___

Two metallic plates form a parallel plate capacitor. The distance between the plates is ‘d’. A metal sheet of thickness d/2 and of area equal to area of each plate is introduced between the plates. What will be the ratio of the new capacitance to the original capacitance of the capacitor?

For a particle in uniform circular motion, the acceleration a at any point P(R, θ) on the circular path of radius R is (when θ is measured from the positive x-axis and v is uniform speed):

A proton, a neutron, an electron and an α-particle have same energy. If λ_p, λ_n, λ_e and λ_α are the de Broglie’s wavelengths of proton, neutron, electron and α particle respectively, then choose the correct relation from the following:

Sodium light of wavelengths 650 nm and 655 nm is used to study diffraction at a single slit of aperture 0.5 mm. The distance between the slit and the screen is 2.0 m. The separation between the positions of the first maxima of diffraction pattern obtained in the two cases is _____ × 10^–5 m.

The interference pattern is obtained with two coherent light sources of intensity ratio 4 : 1. And the ratio

$\frac{l_{max}+l_{min}}{l_{max}-l_{min} }$

is 5/x. Then, the value of x will be equal to:

Which of the following figure represents the variation of $ln (\frac{R}{R_0})$ with $ln\ A$?
(if $R$ = radius of a nucleus and $A$ = its mass number)

The ratio of specific heats

$(\frac{c_p}{c_v}) $

in terms of degree of freedom (f) is given by:

A long solenoid carrying a current produces a magnetic field B along its axis. If the current is doubled and the number of turns per cm is halved, the new value of magnetic field will be equal to

The magnetic field at the centre of a circular coil of radius r, due to current I flowing through it, is B. The magnetic field at a point along the axis at a distance $\frac{r}{2}$ from the centre is :

A Carnot engine whose heat sinks at 27°C, has an efficiency of 25%. By how many degrees should the temperature of the source be changed to increase the efficiency by 100% of the original efficiency?

A sinusoidal voltage V(t) = 210 sin 3000 t volt is applied to a series LCR circuit in which L = 10 mH, C = 25 μF and R = 100 Ω. The phase difference (Φ) between the applied voltage and resultant current will be:

A baseband signal of 3.5 MHz frequency is modulated with a carrier signal of 3.5 GHz frequency using amplitude modulation method. What should be the minimum size of antenna required to transmit the modulated signal?

A projectile is launched at an angle ‘α’ with the horizontal with a velocity $20$ $ms^{–1}$. After $1 0$ $s$, its inclination with horizontal is ‘β’. The value of tanβ will be ($g$ = $10$ $ms^{–2}$).

Two cells of same emf but different internal resistances r₁ and r₂ are connected in series with a resistance R. The value of resistance R, for which the potential difference across second cell is zero, is

If n represents the actual number of deflections in a converted galvanometer of resistance G and shunt resistance S. Then the total current I when its figure of merit is K will be

A transistor is used in common-emitter mode in an amplifier circuit. When a signal of 10 mV is added to the base-emitter voltage, the base current changes by 10 mA and the collector current changes by 1.5 mA. The load resistance is 5 kW. The voltage gain of the transistor will be ___.

A Carnot engine takes 5000 kcal of heat from a reservoir at 727°C and gives heat to a sink at 127°C. The work done by the engine is

In the figure, a very large plane sheet of positive charge is shown. $P_1$ and $P_2$ are two points at distance $l $ and $2l$ from the charge distribution. If $σ $ is the surface charge density, then the magnitude of electric fields $E_1$ and $E_2$ and $P_1$ and $P_2$ respectively are

If $Z=\frac {A^2B^3}{C^4},$ then the relative error in Z will be

A monkey of mass $50 \,kg$ climbs on a rope which can withstand the tension $(T)$ of $350 \,N$ If monkey initially climbs down with an acceleration of $4\, m / s ^2$ and then climbs up with an acceleration of $5 \,m / s ^2$ Choose the correct option $\left( g =10\, m / s ^2\right)$

Given below are two statements:
Statement-I : The reactance of an ac circuit is zero. It is possible that the circuit contains a capacitor and an inductor.
Statement-II : In ac circuit, the average power delivered by the source never becomes zero.
In the light of the above statements, choose the correct answer from the options given below.

The soft-iron is a suitable material for making an electromagnet. This is because soft-iron has

The distance between Sun and Earth is R. The duration of year if the distance between Sun and Earth becomes 3R will be :