JEE Main 2020 Physics Paper: 3 Sep, Shift 2

Hydrogen ion and singly ionized helium atom are accelerated, from rest, through the same potential difference. The ratio of final speeds of hydrogen and helium ions is close to:

Two resistors 400$\Omega$ and 800$\Omega$ are connected in series across a 6 V battery. The potential difference measured by a voltmeter of 10 k$\Omega$ across 400 $\Omega$ resistor is close to:

Two sources of light emit X-rays of wavelength 1 nm and visible light of wavelength 500 nm, respectively. Both the sources emit light of the same power 200 W. The ratio of the number density of photons of X-rays to the number density of photons of the visible light of the given wavelengths is:

A uniform magnetic field B exists in a direction perpendicular to the plane of a square loop made of a metal wire. The wire has a diameter of 4 mm and a total length of 30 cm. The magnetic field changes with time at a steady rate $\frac{dB}{dt}$ = 0.032 Ts–1. The induced current in the loop is close to (Resistivity of the metal wire is 1.23 $\times$ 10–8 $\Omega$m)

The electric field of a plane electromagnetic wave propagating along the x direction in vacuum is $\vec{E} = E_0\hat{j}\cos(\omega t - kx)$.

The magnetic field $\vec{B}$, at the moment t = 0 is:

Concentric metallic hollow spheres of radii R and 4R hold charges Q1 and Q2 respectively. Given that surface charge densities of the concentric spheres are equal, the potential difference V(R) – V(4R) is:

The mass density of a planet of radius R varies with the distance r from its centre as $\rho$(r) = $\rho_0 (1$ $- \frac{r^2}{R^2})$.

Then the gravitational field is maximum at:

A perfectly diamagnetic sphere has a small spherical cavity at its centre, which is filled with a paramagnetic substance. The whole system is placed in a uniform magnetic field $\vec{B}$. Then the field inside the paramagnetic substance is:

A galvanometer coil has 500 turns and each turn has an average area of 3 $\times$ 10–4 m2. If a torque of 1.5 Nm is required to keep this coil parallel to a magnetic field when a current of 0.5 A is flowing through it, the strength of the field (in T) is ______.

The radius R of a nucleus of mass number A can be estimated by the formula

R = (1.3 $\times$ 10–15)A1/3 m.

It follows that the mass density of a nucleus is of the order of:

(Mprot. $\cong$ Mneut $\simeq$ 1.67 $\times$ 10–27 kg)

A block of mass m attached to a massless spring is performing oscillatory motion of amplitude ‘A’ on a frictionless horizontal plane. If half of the mass of the block breaks off when it is passing through its equilibrium point, the amplitude of oscillation for the remaining system become fA. The value of f is:

When an object is kept at a distance of 30 cm from a concave mirror, the image is formed at a distance of 10 cm from the mirror. If the object is moved with a speed of 9 cms–1, the speed (in cms–1) with which image moves at that instant is ____.

A massless equilateral triangle EFG of side ‘a’ (As shown in figure) has three particles of mass m situated at its vertices. The moment of inertia of the system about the line EX perpendicular to EG in the plane of EFG is $\frac{N}{20}$ ma2 where N is an integer. The value of N is _____.

A uniform rod of length ‘$l$’ is pivoted at one of its ends on a vertical shaft of negligible radius. When the shaft rotates at angular speed $\omega$ the rod makes an angle $\theta$ with it (see figure). To find $\theta$ equate the rate of change of angular momentum (direction going into the paper) $\frac{ml^{2}}{12}\omega^{2}\sin\theta\cos\theta$ about the centre of mass (CM) to the torque provided by the horizontal and vertical forces FH and FV about the CM. The value of $\theta$ is then such that:

Which of the following will NOT be observed when a multimeter (operating in resistance measuring mode) probes connected across a component, are just reversed?

If a semiconductor photodiode can detect a photon with a maximum wavelength of 400 nm, then its band gap energy is:

Planck’s constant h = 6.63 $\times$ 10–34 J.s. Speed of light c = 3 $\times$ 108 m/s

If minimum possible work is done by a refrigerator in converting 100 grams of water at 0oC to ice, how much heat (in calories) is released to the surroundings at temperature 27oC (Latent heat of ice = 80 Cal/gram) to the nearest integer?

To raise the temperature of a certain mass of gas by 50oC at a constant pressure, 160 calories of heat is required. When the same mass of gas is cooled by 100oC at constant volume, 240 calories of heat is released. How many degrees of freedom does each molecule of this gas have (assume gas to be ideal)?

A calorimeter of water equivalent 20 g contains 180 g of water at 25oC. ‘m’ grams of steam at 100oC is mixed in it till the temperature of the mixure is 31oC. The value of ‘m’ is close to: (Latent heat of water = 540 cal g–1, specific heat of water = 1 cal g–1oC–1)

Amount of solar energy received on the earth’s surface per unit area per unit time is defined as solar constant. Dimension of solar constant is:

Two light waves having the same wavelength $\lambda$ in vacuum are in phase initially. Then the first wave travels a path L1 through a medium of refractive index n1 while the second wave travels a path of length L2 through a medium of refractive index n2. After this the phase difference between the two waves is:

A block starts moving up an inclined plane of inclination 30° with an initial velocity of v0. It comes back to its initial position with velocity $\frac{v_0}{2}$. The value of the coefficient of kinetic friction between the block and the inclined plane is close to $\frac{I}{1000}$. The nearest integer to I is____.

A particle is moving unidirectionally on a horizontal plane under the action of a constant power supplying energy source. The displacement (s) - time (t) graph that describes the motion of the particle is (graphs are drawn schematically and are not to scale):