List of top Questions asked in JEE Main

Given below are two statements: One is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): In an uniform magnetic field, speed and energy remains the same for a moving charged particle.
Reason (R): Moving charged particle experiences magnetic force perpendicular to its direction of motion.

Two identical cells each of emf 1.5 V are connected in parallel across a parallel combination of two resistors each of resistance 20 W. A voltmeter connected in the circuit measures 1.2 V. The internal resistance of each cell is

Identify the pair of physical quantities which have different dimensions.
A wire of resistance $R_1$ is drawn out so that its length is increased by twice of its original length The ratio of new resistance to original resistance is:
The current sensitivity of a galvanometer can be increased by: 
(A) decreasing the number of turns 
(B) increasing the magnetic field 
(C) decreasing the area of the coil 
(D) decreasing the torsional constant of the spring Choose the most appropriate answer from the options given below:
As shown in the figure, a metallic rod of linear density \(0.45\ kg m^{-1}\) is lying horizontally on a smooth incline plane which makes an angle of 45° with the horizontal. The minimum current flowing in the rod required to keep it stationary, when \(0.15 T\) magnetic field is acting on it in the vertical upward direction, will be: {Use \(g = 10 m/s^2\)}
metallic rod of linear density
Three masses \(M =100 \,kg , m _1=10\, kg\) and \(m _2=20 \,kg\) are arranged in a system as shown in figure All the surfaces are frictionless and strings are inextensible and weightless The pulleys are also weightless and frictionless A force \(F\) is applied on the system so that the mass \(m _2\) moves upward with an acceleration of \(2\, ms ^{-2}\) The value of \(F\) is : (Take \(\text g=10\;ms^-2\))
\(B_X\) and \(B_Y\) are the magnetic field at the centre of two coils of two coils \(X\) and \(Y\) respectively, each carrying equal current If coil \(X\) has \(200\) turns and \(20\, cm\) radius and coil \(Y\) has \(400\) turns and \(20 \,cm\) radius, the ratio of \(B_X\) and \(B_Y\) is
As shown in the figure, after passing through the medium 1. The speed of light v2 in medium 2 will be: (Given \(c = 3 \times 10^8 ms^{-1}\))
speed of light v2 in medium 2

The current \(I\) in the given circuit will be

\(7\) mole of certain monoatomic ideal gas undergoes a temperature increase of \(40\, K\) at constant pressure The increase in the internal energy of the gas in this process is (Given \(R =83\, JK ^{-1}\, mol ^{-1}\))
In normal adjustment, for a refracting telescope, the distance between objective and eye piece is $30\,cm$ The focal length of the objective, when the angular magnification of the telescope is 2, will be:
A radio can tune to any station in $6\, MHz$ to $10\, MHz$ band The value of corresponding wavelength bandwidth will be :
The disintegration rate of a certain radioactive sample at any instant is $4250$ disintegrations per minute $10$ minutes later, the rate becomes $2250 $ disintegrations per minute The approximate decay constant is : (Take $\log _{10} 188=0274$ )
A parallel beam of light of wavelength $900 \,nm$ and intensity $100 \,Wm ^{-2}$ is incident on a surface perpendicular to the beam Tire number of photons crossing $1 \,cm ^2$ area perpendicular to the beam in one second is :
The equation $\lambda=\frac{1227}{ x } nm$ can be used to find the de-Brogli wavelength of an electron In this equation $x$ stands for : Where, $m =$ mass of electron $P =$ momentum of electron $K =$ Kinetic energy of electron $V=$ Accelerating potential in volts for electron
The half life period of a radioactive substance is 60 days The time taken for $\frac{7}{8}$ th of its original mass to disintegrate will be :
In the case of amplitude modulation to avoid distortion the modulation index $(\mu)$ should be:
In young's double slit experiment, the fringe width is $12\, mm$ If the entire arrangement is placed in water of refractive index $\frac{4}{3}$, then the fringe width becomes (in $mm$ )
The magnetic field of a plane electromagnetic wave is given by $\vec{ B }=2 \times 10^{-8} \sin \left(05 \times 10^3 x +15 \times 10^{11} t \right) \hat{ j } T$ The amplitude of the electric field would be
In a series LR circuit $X_L=R$ and power factor of the circuit is $P _1$ When capacitor with capacitance $C$ such that $X _{ L }= X _{ C }$ is put in series, the power factor becomes $P _2$ The ratio $\frac{ P _1}{ P _2}$ is
A charge particle is moving in a uniform magnetic field $(2 \hat{ i }+3 \hat{ j }) T$ If it has an acceleration of $(\alpha \hat{i}-4 \hat{j}) m / s ^2$, then the value of $\alpha$ will be
The total charge on the system of capacitance $C _1=1\, \mu F , C _2=2 \,\mu F , C _3=4 \,\mu F $ and $C _4=3\, \mu F$ connected in parallel is (Assume a battery of $20 \,V$ is connected to the combination)
When a particle executes simple Harmonicmotion, the nature of graph of velocity asfunction of displacement will be :
Consider two containers A and B containing monoatomic gases at the same Pressure (P), Volume (V) and Temperature (T). The gas in A is compressed isothermally to \(\frac{1}{8}\) of its original volume while the gas in B is com pressed adiabatically to \(\frac{1}{8}\) of its original volume. The ratio of final pressure of gas in B to that of gas in A is