List of top Questions asked in JEE Main

The terminal velocity \((v_t)\) of the spherical rain drop depends on the radius (r) of the spherical rain drop as
The relation between root mean square speed \((v_{rms})\) and most probable speed (\(v_p\)) for the molar mass M of oxygen gas molecule at the temperature of 300 K will be
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
large plane sheet of positive charge
Match List-I with List-II
List-IList-II
(A) AC generator(I) Detects the presence of current in the circuit
(B) Galvanometer(II) Converts mechanical energy into electrical energy
(C) Transformer(III) Works on the principle of resonance in AC circuit
(D) Metal detector(IV) Changes an alternating voltage for smaller or greater value
Choose the correct answer from the options given below.
The bulk modulus of a liquid is 3 × 1010 Nm-2. The pressure required to reduce the volume of liquid by 2% is

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
The equation of current in a purely inductive circuit is $5 \sin \left(49 \pi t -30^{\circ}\right)$ If the inductance is $30\, mH$ then the equation for the voltage across the inductor, will be: $\left\{\text { Let } \pi=\frac{22}{7}\right\}$
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 $mm$ )