List of top Questions asked in JEE Main

An infinitely long hollow conducting cylinder with radius R carries a uniform current along its surface.
Choose the correct representation of magnetic field (B) as a function of radial distance (r) from the axis of cylinder.
A radar sends an electromagnetic signal of electric field (E0) = 2.25 V/m and magnetic field (B0) = 1.5 × 10–8 T which strikes a target on line of sight at a distance of 3 km in a medium. After that, a part of signal (echo) reflects back towards the radar with same velocity and by same path. If the signal was transmitted at time t = 0 from radar, then after how much time echo will reach to the radar?
The aperture of the objective is 24.4 cm. The resolving power of this telescope, if a light of wavelength 2440 Å is used to see the object will be:
The de Broglie wavelengths for an electron and a photon are λe and λp, respectively. For the same kinetic energy of electron and photon, which of the following presents the correct relation between the de Broglie wavelengths of two?
The Q-value of a nuclear reaction and kinetic energy of the projectile particle, Kp are related as :

In the following circuit, the correct relation between output (Y) and inputs A and B will be:
 

Fig. Circuit
For using a multimeter to identify diode from electrical components, choose the correct statement out of the following about the diode:

Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R.

Assertion A :n-p-n transistor permits more current than a p-n-p transistor.
Reason R: Electrons have greater mobility as a charge carrier.

Choose the correct answer from the options given below:

Match List-I with List-II.

                    List - IList - II
A.Television signal i.03 KHz 
B.Radio signalii.20 KHz
C.High Quality Musiciii.02 MHz
D.Human speechiv.06 MHz 

Choose the correct answer from the options given below:

 

The velocity of sound in a gas, in which two wavelengths, 4.08 m and 4.16 m produce 40 beats in 12 s, will be:
A disc of mass 1 kg and radius R is free to rotate about a horizontal axis passing through its centre and perpendicular to the plane of disc. A body of same mass as that of disc of fixed at the highest point of the disc. Now the system is released, when the body comes to the lowest position, it angular speed will be \(4\sqrt {\frac {x}{3R}}\) rad s−1 where x = ______ .(g = 10 ms–2)
In an experiment of determine the Young’s modulus of wire of a length exactly 1 m, the extension in the length of the wire is measured as 0.4 mm with an uncertainty of ±0.02 mm when a load of 1 kg is applied. The diameter of the wire is measured as 0.4 mm with an uncertainty of ±0.02 mm when a load of 1 kg is applied. The diameter of the wire is measured as 0.4 mm with an uncertainty of ± 0.01 mm. The error in the measurement of Young’s modulus (ΔY) is found to be x × 1010 Nm–2. The value of x is ___.
(Take g=10 m/s2)
When a car is approaching the observer, the frequency of horn is 100 Hz. After passing the observer, it is 50 Hz. If the observer moves with the car, the frequency will be \(\frac x3\) Hz, where x = _____ .
A composite parallel plate capacitor is made up of two different dielectric materials with different thickness (t1 and t2) as shown in figure. The two different dielectric materials are separated by a conducting foil F. The voltage of the conducting foil is _____V.
A composite parallel plate capacitor is made up of two different dielectric materials with different thickness

The intensity of the light from a bulb incident on a surface is 0.22 W/m2. The amplitude of the magnetic field in this light-wave is ___ × 10–9 T.

(Given : Permittivity of vacuum ε0 = 8.85 × 10–12C2N–1–m–2, speed of light in vacuum c = 3 × 108 ms–1)

As per the given figure, two plates A and B of thermal conductivity K and 2 K are joined together to form a compound plate. The thickness of plates are 4.0 cm and 2.5 cm, respectively and the area of cross-section is 120 cm2 for each plate. The equivalent thermal conductivity of the compound plate is \((1+\frac{5}{α})K,\) then the value of α will be ___.

As per the given figure, two plates A and B of thermal conductivity K and 2 K are joined together to form a compound plate

In the hydrogen spectrum, λ be the wavelength of first transition line of Lyman series. The wavelength difference will be “aλ” between the wavelength of 3rd transition line of the Paschen series and that of 2nd transition line of Balmer series where a = ______.
A body is performing simple harmonic with an amplitude of 10 cm. The velocity of the body was tripled by air jet when it is at 5 cm from its mean position. The new amplitude of vibration is \(\sqrt x\) cm. The value of x is ___.
The variation of applied potential and current flowing through a given wire is shown in figure. The length of wire is 31.4 cm. The diameter of wire is measured as 2.4 cm. The resistivity of the given wire is measured as x × 10–3Ω cm. The value of x is____. [Take π = 3.14]
In the circuit shown below, maximum Zener diode current will be ________ mA.
circuit for maximum Zener diode current
A potentiometer wire of length 10 m and resistance 20 Ω is connected in series with a 25 V battery and an external resistance 30 Ω. A cell of emf E in secondary circuit is balanced by 250 cm long potentiometer wire. The value of E (in volt) is \(\frac {x}{10}\). The value of \(x\) is ______.
Two travelling waves of equal amplitudes and equal frequencies move in opposite directions along a string. They interfere to produce a stationary wave whose equation is given by \(y = (10 cos \ \pi x\ sin \frac {2\pi t}{T})\) cm. The amplitude of the particle at \(x = \frac 43\) cm will be _______ cm.
In the given circuit, the value of current \(I_L\) will be __________ mA. (When \(R_L = 1\ kΩ\))
In the given circuit, the value of current IL
A sample contains \(10^{–2}\) kg each of two substances A and B with half lives 4 s and 8 s respectively. The ratio of their atomic weights is 1 : 2. The ratio of the amounts of A and B after 16 s is \(\frac {x}{100}\). The value of \(x\) is ______.
A ray of light is incident at an angle of incidence \(60º\) on the glass slab of refractive index \(\sqrt 3.\) After refraction, the light ray emerges out from other parallel faces and lateral shift between incident ray and emergent ray is \(4\sqrt 3.\) cm. The thickness of the glass slab is ______ cm.