List of top Questions asked in JEE Main

Among the given oxides of nitrogen; N₂O, N₂O₃, N₂O₄ and N₂O₅, the number of compound/(s) having N – N bond is:

Identify the incorrect statement from the following

An object is thrown vertically upwards. At its maximum height, which of the following quantity becomes zero?

For a specific wavelength 670 nm of light from a galaxy moving with velocity ν, the observed wavelength is 670.7 nm. The value of ν is

The velocity of upper layer of water in a river is \(36\ kmh^{–1}\). Shearing stress between horizontal layers of water is \(10^{–3} Nm^{–2}\). Depth of the river is ______ m. (Co-efficient of viscosity of water is \(10^{–2} Pa.s\))

A bar magnetic having a magnetic moment of 2.0 × 10⁵ JT^–1, is placed along the direction of uniform magnetic field of magnitude B = 14 × 10^–5 T. The work done in rotating the magnet slowly through 60° from the direction of field is:

Two buses P and Q start from a point at the same time and move in a straight line and their positions are represented by X_P(t) = αt + βt² and X_Q(t) = ft – t². At what time, both the buses have same velocity?

A ball is projected vertically upward with an initial velocity of 50 ms^–1 at t = 0 s. At t = 2 s, another ball is projected vertically upward with same velocity. 
At t = _____s, second ball will meet the first ball. (g = 10 ms^–2)

The positive feedback is required by an amplifier to act an oscillator. The feedback here means:

If a wave gets refracted into a denser medium, then which of the following is true?

The light of two different frequencies whose photons have energies 3.8 eV and 1.4 eV respectively, illuminate a metallic surface whose work function is 0.6 eV successively. The ratio of maximum speeds of emitted electrons for the two frequencies respectively will be

A parallel plate capacitor with plate area A and plate separation d = 2 m has a capacitance of 4 μF. The new capacitance of the system, if half of the space between them is filled with a dielectric material of dielectric constant K = 3 (as shown in figure), will be :

The susceptibility of a paramagnetic material is \(99\). The permeability of the material in Wb/A-m, is 
[Permeability of free space \(μ_0\) = \(4π × 10^{–7}\) Wb/A-m]

A mass of \(10\) kg is suspended vertically by a rope of length \(5\) m from the roof. A force of \(30\) N is applied at the middle point of rope in horizontal direction. The angle made by upper half of the rope with vertical is \(θ\) = \(tan^{–1} (x × 10^{–1})\). The value of \(x\) is _______.(Given, \(g = 10\; m/s^2\))

Resistance of the wire is measured as 2 Ω and 3 Ω at 10°C and 30°C respectively. Temperature co-efficient of resistance of the material of the wire is:

Two point charges A and B of magnitude \(+8 \times 10^{–6} C\) and \(-8 \times 10^{–6} C\) respectively are placed at a distance d apart. The electric field at the middle point O between the charges is \(6.4 \times 10^{4} NC^{–1}\). The distance ‘d’ between the point charges A and B is:

When a gas filled in a closed vessel is heated by raising the temperature by 1ºC, its pressure increases by 0.4%. The initial temperature of the gas is _____ K.

A transistor is used in an amplifier circuit in common emitter mode. If the base current changes by 100μA, it brings a change of 10mA in collector current. If the load resistance is 2kΩ and input resistance is 1kΩ, the value of power gain is \(x×10^4\). The value of x is _______.

Two long current carrying conductors are placed parallel to each other at a distance of 8 cm between them. The magnitude of magnetic field produced at mid-point between the two conductors due to current flowing in them is 30 μT. The equal current flowing in the two conductors is:

Two point charges Q each are placed at a distance d apart. A third point charge q is placed at a distance x from mid-point on the perpendicular bisector. The value of x at which charge q will experience the maximum Coulombs force is :

The percentage decrease in the weight of a rocket, when taken to a height of 32 km above the surface of earth will, be:
(Radius of earth = 6400 km)

The activity of a radioactive material is 2.56 × 10^–3 Ci. If the half life of the material is 5 days, after how many days the activity will become 2 × 10^–5 Ci?

Given below are two statements.
Statement-I: The law of gravitation holds good for any pair of bodies in the universe.
Statement-II: The weight of any person becomes zero when the person is at the centre of the earth.
In the light of the above statements, choose the correct answer from the options given below