Join WhatsApp Icon JEE WhatsApp Group

NTA JEE Main 16th March 2021 Shift 1 - Physics

For the following questions answer them individually

A block of 200 g mass moves with a uniform speed in a horizontal circular groove, with vertical side walls of radius 20 cm. If the block takes 40 s to complete one round, the normal force by the side walls of the groove is:

A block of mass $$m$$ slides along a floor while a force of magnitude $$F$$ is applied to it at an angle $$\theta$$ as shown in figure. The coefficient of kinetic friction is $$\mu_K$$. Then, the block's acceleration $$a$$ is given by: ($$g$$ is acceleration due to gravity)

The maximum and minimum distances of a comet from the Sun are $$1.6 \times 10^{12}$$ m and $$8.0 \times 10^{10}$$ m respectively. If the speed of the comet at the nearest point is $$6 \times 10^{4}$$ m s$$^{-1}$$, the speed at the farthest point is:

Four equal masses, $$m$$ each are placed at the corners of a square of length $$l$$ as shown in the figure. The moment of inertia of the system about an axis passing through $$A$$ and parallel to $$DB$$ would be:

The pressure acting on a submarine is $$3 \times 10^5$$ Pa at a certain depth. If the depth is doubled, the percentage increase in the pressure acting on the submarine would be: (Assume that atmospheric pressure is $$1 \times 10^5$$ Pa, density of water is $$10^3$$ kg m$$^{-3}$$, g = 10 ms$$^{-2}$$)

The volume $$V$$ of an enclosure contains a mixture of three gases, 16 g of oxygen, 28 g of nitrogen and 44 g of carbon dioxide at absolute temperature $$T$$. Consider $$R$$ as universal gas constant. The pressure of the mixture of gases is:

Time period of a simple pendulum is $$T$$ inside a lift when the lift is stationary. If the lift moves upwards with an acceleration $$\frac{g}{2}$$, the time period of pendulum will be:

For changing the capacitance of a given parallel plate capacitor, a dielectric material of dielectric constant $$K$$ is used, which has the same area as the plates of the capacitor. The thickness of the dielectric slab is $$\frac{3}{4}d$$, where $$d$$ is the separation between the plates of parallel plate capacitor. The new capacitance $$C'$$ in terms of original capacitance $$C_0$$ is given by the following relation:

A conducting wire of length $$l$$, area of cross-section $$A$$ and electric resistivity $$\rho$$ is connected between the terminals of a battery. A potential difference $$V$$ is developed between its ends, causing an electric current. If the length of the wire of the same material is doubled and the area of cross-section is halved, the resultant current would be:

A bar magnet of length 14 cm is placed in the magnetic meridian with its north pole pointing towards the geographic north pole. A neutral point is obtained at a distance of 18 cm from the center of the magnet. If $$B_H = 0.4$$ G, the magnetic moment of the magnet is (1 G = $$10^{-4}$$ T):

A conducting bar of length $$L$$ is free to slide on two parallel conducting rails as shown in the figure.


Two resistors $$R_1$$ and $$R_2$$ are connected across the ends of the rails. There is a uniform magnetic field $$\vec{B}$$ pointing into the page. An external agent pulls the bar to the left at a constant speed $$v$$. The correct statement about the directions of induced currents $$I_1$$ and $$I_2$$ flowing through $$R_1$$ and $$R_2$$ respectively is:

A plane electromagnetic wave of frequency 500 MHz is traveling in a vacuum along the $$y$$-direction. At a particular point in space and time, $$\vec{B} = 8.0 \times 10^{-8}\hat{z}$$ T. The value of the electric field at this point is: (speed of light = $$3 \times 10^{8}$$ ms$$^{-1}$$; $$\hat{x}, \hat{y}, \hat{z}$$ are unit vectors along $$x, y$$ and $$z$$ direction.)

For an electromagnetic wave travelling in free space, the relation between average energy densities due to electric ($$U_e$$) and magnetic ($$U_m$$) fields is:

The angle of deviation through a prism is minimum when


(A) Incident ray and emergent ray are symmetric to the prism
(B) The refracted ray inside the prism becomes parallel to its base
(C) Angle of incidence is equal to that of the angle of emergence
(D) When angle of emergence is double the angle of incidence
Choose the correct answer from the options given below:

One main scale division of a vernier callipers is $$a$$ cm and $$n^{th}$$ division of the vernier scale coincide with $$(n-1)^{th}$$ division of the main scale. The least count of the callipers in mm is:

Consider a frame that is made up of two thin massless rods $$AB$$ and $$AC$$ as shown in the figure. A vertical force $$\vec{P}$$ of magnitude 100 N is applied at point $$A$$ of the frame.


Suppose the force $$\vec{P}$$ is resolved parallel to the arms $$AB$$ and $$AC$$ of the frame. The magnitude of the resolved component along the arm $$AC$$ is $$x$$ N. The value of $$x$$, to the nearest integer, is ________.
[Given: $$\sin(35^\circ) = 0.573, \cos(35^\circ) = 0.819, \sin(110^\circ) = 0.939, \cos(110^\circ) = -0.342$$]

Backspace
789
456
123
0.-
Clear All

Consider a 20 kg uniform circular disk of radius 0.2 m. It is pin supported at its center and is at rest initially. The disk is acted upon by a constant force $$F = 20$$ N through a massless string wrapped around its periphery as shown in the figure.


Suppose the disk makes $$n$$ number of revolutions to attain an angular speed of 50 rad s$$^{-1}$$. The value of $$n$$, to the nearest integer, is ________.
[Given: In one complete revolution, the disk rotates by 6.28 rad]

Backspace
789
456
123
0.-
Clear All

A ball of mass 10 kg moving with a velocity $$10\sqrt{3}$$ m s$$^{-1}$$ along $$X$$-axis, hits another ball of mass 20 kg which is at rest. After the collision, the first ball comes to rest and the second one disintegrates into two equal pieces. One of the pieces starts moving along $$Y$$-axis at a speed of 10 m s$$^{-1}$$. The second piece starts moving at a speed of 20 m s$$^{-1}$$ at an angle $$\theta$$ (degree) with respect to the $$X$$-axis. The configuration of pieces after the collision is shown in the figure. The value of $$\theta$$ to the nearest integer is ________.

Backspace
789
456
123
0.-
Clear All

A sinusoidal voltage of peak value 250 V is applied to a series LCR circuit, in which $$R = 8$$ $$\Omega$$, $$L = 24$$ mH and $$C = 60$$ $$\mu$$F. The value of power dissipated at resonant condition is $$x$$ kW. The value of $$x$$ to the nearest integer is ________.

Backspace
789
456
123
0.-
Clear All

A fringe width of 6 mm was produced for two slits separated by 1 mm apart. The screen is placed 10 m away. The wavelength of light used is $$x$$ nm. The value of $$x$$ to the nearest integer is ________.

Backspace
789
456
123
0.-
Clear All

The first three spectral lines of H-atom in the Balmer series are given $$\lambda_1, \lambda_2, \lambda_3$$ considering the Bohr atomic model, the wave lengths of first and third spectral lines $$\left(\frac{\lambda_1}{\lambda_3}\right)$$ are related by a factor of approximately $$x \times 10^{-1}$$. The value of $$x$$, to the nearest integer, is ________.

Backspace
789
456
123
0.-
Clear All

The value of power dissipated across the zener diode ($$V_z = 15$$ V) connected in the circuit as shown in the figure is $$x \times 10^{-1}$$ W.


The value of $$x$$ to the nearest integer is ________.

Backspace
789
456
123
0.-
Clear All