JEE Main 2020 (Online) 7th January Morning Slot

A LCR circuit behaves like a damped harmonic oscillator. Comparing it with a physical spring-mass damped oscillator having damping constant 'b', the correct equivalence would be:

The time period of revolution of electron in its ground state orbit in a hydrogen atom is 1.6 \(\times\) 10-16 s. The frequency of revolution of the electron in its first excited state (in s-1) is :

A parallel plate capacitor has plates of area A separated by distance 'd' between them. It is filled with a dielectric which has a dielectric constant that varies as k(x) = K(1 + \(\alpha\)x) where 'x' is the distance measured from one of...

Three point particles of masses 1.0 kg, 1.5 kg and 2.5 kg are placed at three corners of a right angle triangle of sides 4.0 cm, 3.0 cm and 5.0 cm as shown in the figure. The center of mass of the system is at a point:

The current I1 (in A) flowing through 1 \(\Omega\) resistor in the following circuit is :

A beam of electromagnetic radiation of intensity 6.4 × 10–5 W/cm2 is comprised of wavelength,
\(\lambda\) = 310 nm. It falls normally on a metal (work function \(\phi\) = 2eV) of surface area of 1 cm2. If one
in 103 photons ejects an elct...

Consider a circular coil of wire carrying constant current I, forming a magnetic dipole. The magnetic flux through an infinite plane that contains the circular coil and excluding the circular coil area is given by \(\phi\)i. The magnetic f...

A long solenoid of radius R carries a time (t) - dependent current I(t)=I0t(1 - t). A ring of radius 2R is placed coaxially near its middle. During the time interval 0 \(\le\) t \(\le\) 1, the induced current (IR) and the induced EMF(VR...

A loop ABCDEFA of straight edges has six corner points A(0, 0, 0), B(5, 0, 0), C(5, 5, 0), D (0, 5,
0), E(0, 5, 5) and F(0, 0, 5). The magnetic field in this region is \(\overrightarrow B = \left( {3\widehat i + 4\widehat k} \right)T\)
. T...

If the magnetic field in a plane electromagnetic wave is given by
\(\overrightarrow B\) = 3 \(\times\) 10-8 sin(1.6 \(\times\) 103x + 48 \(\times\) 1010t)\(\widehat j\) T, then what will be expression for electric field ?

Which of the following gives a reversible operation?

Two infinite planes each with uniform surface charge density to are kept in such a way that the angle between them is 30o. The electric field in the region shown between them is given by :

If we need a magnification of 375 from a compound microscope of tube length 150 mm and an objective of focal length 5 mm, the focal length of the eye-piece, should be close to :

A satellite of mass m is launched vertically upwards with an initial speed u from the surface of the earth. After it reaches height R (R = radius of the earth), it ejects a rocket
of mass \({m \over {10}}\)
so that subsequently the
satellit...

A Carnot engine operates between two reservoirs of temperatures 900 K and 300 K. The engine
performs 1200 J of work per cycle. The heat energy (in J) delivered by the engine to the low
temperature reservoir, in a cycle, is _______.

Two moles of an ideal gas with \({{{C_P}} \over {{C_V}}} = {5 \over 3}\)
are mixed with 3 moles of another ideal gas
with \({{{C_P}} \over {{C_V}}} = {4 \over 3}\). The value of \({{{C_P}} \over {{C_V}}}\) for the
mixture is :

A non-isotropic solid metal cube has coefficients of linear expansion as : 5 \(\times\) 10-5/oC along the x-axis and 5 \(\times\) 10-6/oC along the y and the z-axis. If the coefficient of volume expansion of the solid is C \(\times\) ...

A litre of dry air at STP expands adiabatically to a volume of 3 litres. If \(\gamma\) = 1.40, the work done by air is : (31.4 = 4.6555) [Take air to be an ideal gas]

The radius of gyration of a uniform rod of length \(l\), about an axis passing through a
point \({l \over 4}\) away from the centre of the rod,
and perpendicular to it, is :

As shown in the figure, a bob of mass m is tied by a massless string whose other end portion is wound on a fly wheel (disc) of radius r and mass m. When released from rest the bob starts falling vertically. When it has covered a distance o...

Visible light of wavelength 6000 \(\times\) 10-8 cm falls normally on a single slit and produces a diffraction pattern. It is found that the second diffraction minimum is at 60o from the central maximum. If the first minimum is produced a...

A polarizer - analyser set is adjusted such that the intensity of light coming out of the analyser is just 10% of the original intensity. Assuming that the polarizer - analyser set does not absorb any light, the angle by which the analyser ...

Speed of a transverse wave on a straight wire (mass 6.0 g, length 60 cm and area of cross-section 1.0 mm2) is 90 ms-1. If the Young's modulus of wire is 16 \(\times\) 1011 Nm-2, the extension of wire over its natural length is :

A particle (m = 1 kg) slides down a frictionless track (AOC) starting from rest at a point A (height 2 m). After reaching C, the particle continues to move freely in air as a projectile. When it reaching its highest point P (height 1 m), th...

A 60 HP electric motor lifts an elevator having a maximum total load capacity of 2000 kg. If the frictional force on the elevator is 4000 N, the speed of the elevator at full load is close to : (1 HP = 746 W, g = 10 ms-2)