List of top Physics Questions asked in JEE Main

The displacement of simple harmonic oscillator after 3 seconds starting from its mean position is equal to half of its amplitude. The time period of harmonic motion is :
The charge on capacitor of capacitance 15 μF in the figure given below is 
The charge on capacitor of capacitance
If ρ is the density and η is coefficient of viscosity of fluid which flows with a speed v in the pipe of diameter d, the correct formula for Reynolds number Re is:
A \(\sqrt{34}\) m long ladder weighing 10kg leans on a frictionless wall. Its feet rest on the floor 3m away from the wall as shown in the figure. If Ff and Fw are the reaction forces of the floor and the wall, then ratio of \(\frac{F_w}{F_f}\) will be: (Use g = 10 m/s2)
A √(34)m long ladder weighing 10kg
A hydrogen atom in its ground state absorbs 10.2 eV of energy. The angular momentum of electron of the hydrogen atom will increase by the value of: (Given, Planck’s constant = \(6.6 × 10^{–34}\) Js).
The current flowing through an ac circuit is given by \(I = 5 \;sin\;(120πt)\;A\). How long will the current take to reach the peak value starting from zero?
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 ___.

Two metallic blocks M1 and M2 of the same cross-section area are connected (as shown in the figure). If the thermal conductivity of M2 is K then the thermal conductivity of M1 will be : [Assume steady state heat conduction]
Two metallic blocks
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)
A parallel plate capacitor is formed by two plates each of area 30p cm2 separated by 1 mm. A material of dielectric strength 3.6 × 107 Vm–1 is filled between the plates. If the maximum charge that can be stored on the capacitor without causing any dielectric breakdown is 7 × 10–6 C, the value of dielectric constant of the material is : [\(\frac{1}{4πε0}\)=9×109\(Nm^2C^{-2}\)]
 
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 ___
The electromagnetic waves travel in a medium at a speed of 2.0 × 108 m/s. The relative permeability of the medium is 1.0. The relative permittivity of the medium will be
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 (\(g\) = \(10\) \(ms^{–2}\)).
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 copper block of mass 5.0 kg is heated to a temperature of 500°C and is placed on a large ice block. What is the maximum amount of ice that can melt? 

[Specific heat of copper 0.39 J g–1 °C–1 and latent heat of fusion of water : 335 J g–1]

Given below are two statements:

Statement-I : Susceptibilities of paramagnetic and ferromagnetic substances increase with decrease in temperature.

Statement-II : Diamagnetism is a result of orbital motions of electrons developing magnetic moments opposite to the applied magnetic field.

Choose the correct answer from the options given below:-

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

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:

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: