JEE Main 2019 Physics Paper: 9 Jan, Shift 2

A power transmission line feeds input power at 2300 V to a step down transformer with its primary windings having 4000 turns. The output power is delivered at 230 V by the transformer. If the current in the primary of the transformer is 5A and its efficiency is 90%, the output current would be:

A series AC circuit containing an inductor (20 mH), a capacitor (120 $\mu$F) and a resistor (60 $\Omega$) is driven by an AC source of 24V/50 Hz. The energy dissipated in the circuit in 60 s is:

A parallel plate capacitor with square plates is filled with four dielectrics of dielectric constants K1, K2, K3, K4 arranged as shown in the figure. The effective dielectric constant K will be:

In the given circuit the internal resistance of the 18 V cell is negligible. If R1 = 400 $\Omega$, R3 = 100 $\Omega$ and R4 = 500 $\Omega$ and the reading of an ideal voltmeter across R4 is 5V, then the value of R2 will be:

A carbon resistance has a following colour code. What is the value of the resistance?

The magnetic field associated with a light wave is given, at the origin, by B = B0 [sin(3.14 $\times$ 107)ct + sin(6.28 $\times$ 107)ct]. If this light falls on a silver plate having a work function of 4.7 eV, what will be the maximum kinetic energy of the photo electrons?

(Take c = 3 $\times$ 108 ms${}^{-1}$, h = 6.6 $\times$ 10$-$34J-s)

The energy associated with electric field is (UE) and with magnetic field is (UB) for an electromagnetic wave in free space. Then:

Two point charges q1 $\left(\sqrt{10}\,\mu\text{C}\right)$ and q2($-$ 25 $\mu$C) are placed on the x-axis at x = 1 m and x = 4 m respectively. The electric field (in V/m) at a point y = 3 m on y-axis is,

[take $\frac{1}{4\pi\varepsilon_0}$ = 9 $\times$ 109 Nm2C${}^{-2}$]

Charge is distributed within a sphere of radius R with a volume charge density $\rho(r) = \frac{A}{r^{2}}e^{-\frac{2r}{a}},$ where A and a are constants. If Q is the total charge of this charge distribution, the radius R is:

The top of a water tank is open to air and its water level is mainted. It is giving out 0.74 m3 water per minute through a circular opening of 2 cm radius in its wall. The depth of the center of the opening from the level of water in the tank is close to:

The energy required to take a satellite to a height 'h' above Earth surface (radius of Earth = 6.4 $\times$ 103 km) is E1 and kinetic energy required for the satellite to be in a circular orbit at this height is E2. The value of h for which E1 and E2 are equal, is

A 15 g mass of nitrogen gas is enclosed in a vessel at a temperature 27oC. Amount of heat transferred to the gas, so that rms velocity of molecules is doubled, is about: [Take R = 8.3 J/K mole]

A mass of 10 kg is suspended vertically by a rope from the roof. When a horizontal force is applied on the rope at some point, the rope deviates at an angle of 45° at the roof point. If the suspended mass is at equilibrium, the magnitude of the force applied is (g = 10 ms${}^{-2}$)

In a car race on straight road, car A takes a time t less than car B at the finish and passes finishing point with a speed '$v$' more than that of car B. Both the cars start from rest and travel with constant acceleration a1 and a2 respectively. Then '$v$' is equal to:

One of the two identical conducting wires of length L is bent in the form of a circular loop and the other one into a circular coil of N identical turns. If the same current is passed in both, the ratio of the magnetic field at the centre of the loop (BL) to that at the center of the coil (BC), i.e. $\frac{B_L}{B_C}$ will be:

A particle having the same charge as of electron moves in a circular path of radius 0.5 cm under the influence of a magnetic field of 0.5 T. If an electric field of 100 V/m makes it to move in a straight path, then the mass of the particle is (Given charge of electron = 1.6 $\times$ 10$-$19 C)

At a given instant, say t = 0, two radioactive substance A and B have equal activities. the ratio $\frac{R_B}{R_A}$ of their activities after time t itself decays with time t as e${}^{-3}$t. If the half-life of A is ln2, the half-life of B is:

A particle is executing simple harmonic motion (SHM) of amplitude A, along the x-axis, about x = 0. When its potential Energy (PE) equals kinetic energy (KE), the position of the particle will be:

A rod of mass 'M' and length '2L' is suspended at its middle by a wire. It exhibits torsional oscillations; If two masses each of 'm' are attached at distance 'L/2' from its centre on both sides, it reduces the oscillation frequency by 20%. The value of ratio m/M is close to:

The position co-ordinates of a particle moving in a 3-D coordinate system is given by x = a cos$\omega$t

y = a sin$\omega$t and

z = a$\omega$t

The speed of the particle is:

Two plane mirrors are inclined to each other such that a ray of light incident on the first mirror (M1) and parallel to the second mirror (M2) is finally reflected from the second mirror (M2) parallel to the first mirror (M1). The angle between the two mirrors will be:

A rod of length 50 cm is pivoted at one end. It is raised such that it makes an angle of 30° from the horizontal as shown and released from rest. Its angular speed when it passes through the horizontal (in rad s${}^{-1}$) will be (g = 10 ms${}^{-2}$)

Ge and Si diodes start conducting at 0.3 V and 0.7 V respectively. In the following figure if Ge diode connection are reversed, the value of V0 changes by: (assume that the Ge diode has large breakdown voltage)

Two Carnot engines A and B are operated in series. The first one, A, receives heat at T1 (= 600 K) and rejects to a reservoir at temperature T2. The second engine B receives heat rejected by the first engine and, in turn, rejects to a heat reservoir at T3 (=400 K). Calculate the temperature T2 if the work outputs of the two engines are equal:

Expression for time in terms of G (universal gravitational constant), h (Planck constant) and c (speed of light) is proportional to:

The pitch and the number of divisions, on the circular scale, for a given screw gauge are 0.5 mm and 100 respectively. When the screw gauge is fully tightened without any object, the zero of its circular scale lies 3 divisions below the mean line.

The readings of the main scale and the circular scale, for a thin sheet, are 5.5 mm and 48 respectively, the thickness of this sheet is:

A musician using an open flute of length 50 cm producess second harmonic sound waves. A person runs towards the musician from another end of hall at a speed of 10 km/h. If the wave speed is 330 m/s, the frequency heard by the running person shall be close to:

In a Young's double slit experiment, the slits are placed 0.320 mm apart. Light of wavelength $\lambda$ = 500 nm is incident on the slits. The total number of bright fringes that are observed in the angular range $-$ 30°$\le \theta \le$30° is:

A force acts on a 2 kg object so that its position is given as a function of time as x = 3t2 + 5. What is the work done by this force in first 5 seconds?