JEE MAIN - Physics (2024 - 9th April Evening Shift)

1
The effective resistance between $$A$$ and $$B$$, if resistance of each resistor is $$R$$, will be :

پاسخ دهید
(A)
$$\frac{8 R}{3}$$
2

In the truth table of the above circuit the value of X and Y are :
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(A)
1, 1
3
Two cars are travelling towards each other at speed of $$20 \mathrm{~m} \mathrm{~s}^{-1}$$ each. When the cars are $$300 \mathrm{~m}$$ apart, both the drivers apply brakes and the cars retard at the rate of $$2 \mathrm{~m} \mathrm{~s}^{-2}$$. The distance between them when they come to rest is :
پاسخ دهید
(B)
100 m
4
A nucleus at rest disintegrates into two smaller nuclei with their masses in the ratio of $$2: 1$$. After disintegration they will move :
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(A)
in opposite directions with speed in the ratio of $$1: 2$$ respectively.
5
A satellite of $$10^3 \mathrm{~kg}$$ mass is revolving in circular orbit of radius $$2 R$$. If $$\frac{10^4 R}{6} \mathrm{~J}$$ energy is supplied to the satellite, it would revolve in a new circular orbit of radius

(use $$g=10 \mathrm{~m} / \mathrm{s}^2, R=$$ radius of earth)
پاسخ دهید
(B)
6 R
6
The magnetic field in a plane electromagnetic wave is $$\mathrm{B}_{\mathrm{y}}=\left(3.5 \times 10^{-7}\right) \sin \left(1.5 \times 10^3 x+0.5 \times 10^{11} t\right) \mathrm{T}$$. The corresponding electric field will be :
پاسخ دهید
(A)
$$E_z=105 \sin \left(1.5 \times 10^3 x+0.5 \times 10^{11} t\right) \mathrm{Vm}^{-1}$$
7
A real gas within a closed chamber at $$27^{\circ} \mathrm{C}$$ undergoes the cyclic process as shown in figure. The gas obeys $$P V^3=R T$$ equation for the path $$A$$ to $$B$$. The net work done in the complete cycle is (assuming $$R=8 \mathrm{~J} / \mathrm{mol} \mathrm{K}$$):

پاسخ دهید
(B)
205J
8
Five charges $$+q,+5 q,-2 q,+3 q$$ and $$-4 q$$ are situated as shown in the figure. The electric flux due to this configuration through the surface $$S$$ is :

پاسخ دهید
(D)
$$\frac{4 q}{\epsilon_0}$$
9
UV light of $$4.13 \mathrm{~eV}$$ is incident on a photosensitive metal surface having work function $$3.13 \mathrm{~eV}$$. The maximum kinetic energy of ejected photoelectrons will be:
پاسخ دهید
(B)
1 eV
10
The $$I$$-$$V$$ characteristics of an electronic device shown in the figure. The device is :

پاسخ دهید
(D)
a zener diode which can be used as a voltage regulator
11
The energy released in the fusion of $$2 \mathrm{~kg}$$ of hydrogen deep in the sun is $$E_H$$ and the energy released in the fission of $$2 \mathrm{~kg}$$ of $${ }^{235} \mathrm{U}$$ is $$E_U$$. The ratio $$\frac{E_H}{E_U}$$ is approximately: (Consider the fusion reaction as $$4_1^1H+2 \mathrm{e}^{-} \rightarrow{ }_2^4 \mathrm{He}+2 v+6 \gamma+26.7 \mathrm{~MeV}$$, energy released in the fission reaction of $${ }^{235} \mathrm{U}$$ is $$200 \mathrm{~MeV}$$ per fission nucleus and $$\mathrm{N}_{\mathrm{A}}= 6.023 \times 10^{23})$$
پاسخ دهید
(A)
7.62
12
A hydrogen atom in ground state is given an energy of $$10.2 \mathrm{~eV}$$. How many spectral lines will be emitted due to transition of electrons?
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(D)
1
13
A proton and a deutron $$(q=+\mathrm{e}, m=2.0 \mathrm{u})$$ having same kinetic energies enter a region of uniform magnetic field $$\vec{B}$$, moving perpendicular to $$\vec{B}$$. The ratio of the radius $$r_d$$ of deutron path to the radius $$r_p$$ of the proton path is:
پاسخ دهید
(C)
$$\sqrt{2}: 1$$
14
The temperature of a gas is $$-78^{\circ} \mathrm{C}$$ and the average translational kinetic energy of its molecules is $$\mathrm{K}$$. The temperature at which the average translational kinetic energy of the molecules of the same gas becomes $$2 \mathrm{~K}$$ is :
پاسخ دهید
(D)
$$117^{\circ} \mathrm{C}$$
15
The excess pressure inside a soap bubble is thrice the excess pressure inside a second soap bubble. The ratio between the volume of the first and the second bubble is:
پاسخ دهید
(B)
$$1: 27$$
16
A spherical ball of radius $$1 \times 10^{-4} \mathrm{~m}$$ and density $$10^5 \mathrm{~kg} / \mathrm{m}^3$$ falls freely under gravity through a distance $$h$$ before entering a tank of water, If after entering in water the velocity of the ball does not change, then the value of $$h$$ is approximately:

(The coefficient of viscosity of water is $$9.8 \times 10^{-6} \mathrm{~N} \mathrm{~s} / \mathrm{m}^2$$)
پاسخ دهید
(A)
2518 m
17
The de-Broglie wavelength associated with a particle of mass $$m$$ and energy $$E$$ is $$h / \sqrt{2 m E}$$. The dimensional formula for Planck's constant is :
پاسخ دهید
(C)
$$\left[\mathrm{ML}^2 \mathrm{~T}^{-1}\right]$$
18
A square loop of side $$15 \mathrm{~cm}$$ being moved towards right at a constant speed of $$2\mathrm{~cm} / \mathrm{s}$$ as shown in figure. The front edge enters the $$50 \mathrm{~cm}$$ wide magnetic field at $$t=0$$. The value of induced emf in the loop at $$t=10 \mathrm{~s}$$ will be :

پاسخ دهید
(A)
zero
19
A $$1 \mathrm{~kg}$$ mass is suspended from the ceiling by a rope of length $$4 \mathrm{~m}$$. A horizontal force '$$F$$' is applied at the mid point of the rope so that the rope makes an angle of $$45^{\circ}$$ with respect to the vertical axis as shown in figure. The magnitude of $$F$$ is :

(Assume that the system is in equilibrium and $$g=10 \mathrm{~m} / \mathrm{s}^2$$)

پاسخ دهید
(B)
10 N
20
The following figure represents two biconvex lenses $$L_1$$ and $$L_2$$ having focal length $$10 \mathrm{~cm}$$ and $$15 \mathrm{~cm}$$ respectively. The distance between $$L_1$$ & $$L_2$$ is :

پاسخ دهید
(A)
25 cm
21
The resultant of two vectors $$\vec{A}$$ and $$\vec{B}$$ is perpendicular to $$\vec{A}$$ and its magnitude is half that of $$\vec{B}$$. The angle between vectors $$\vec{A}$$ and $$\vec{B}$$ is _________$$^\circ$$.
پاسخ دهید
150
22
An electric field $$\vec{E}=(2 x \hat{i}) N C^{-1}$$ exists in space. A cube of side $$2 \mathrm{~m}$$ is placed in the space as per figure given below. The electric flux through the cube is ______ $$\mathrm{Nm}^2 / \mathrm{C}$$.

پاسخ دهید
16
23
To determine the resistance (R) of a wire, a circuit is designed below. The $$V$$-$$I$$ characteristic curve for this circuit is plotted for the voltmeter and the ammeter readings as shown in figure. The value of $R$ is _________ $$\Omega$$.

پاسخ دهید
2500
24
A circular disc reaches from top to bottom of an inclined plane of length $$l$$. When it slips down the plane, if takes $$t \mathrm{~s}$$. When it rolls down the plane then it takes $$\left(\frac{\alpha}{2}\right)^{1 / 2} t \mathrm{~s}$$, where $$\alpha$$ is _________.
پاسخ دهید
3
25
A force $$(3 x^2+2 x-5) \mathrm{N}$$ displaces a body from $$x=2 \mathrm{~m}$$ to $$x=4 \mathrm{~m}$$. Work done by this force is ________ J.
پاسخ دهید
58
26
A particle of mass $$0.50 \mathrm{~kg}$$ executes simple harmonic motion under force $$F=-50(\mathrm{Nm}^{-1}) x$$. The time period of oscillation is $$\frac{x}{35} s$$. The value of $$x$$ is _________.

(Given $$\pi=\frac{22}{7}$$)
پاسخ دهید
22
27
At room temperature $$(27^{\circ} \mathrm{C})$$, the resistance of a heating element is $$50 \Omega$$. The temperature coefficient of the material is $$2.4 \times 10^{-4}{ }^{\circ} \mathrm{C}^{-1}$$. The temperature of the element, when its resistance is $$62 \Omega$$, is __________$${ }^{\circ} \mathrm{C}$$.
پاسخ دهید
1027
28
A straight magnetic strip has a magnetic moment of $$44 \mathrm{~Am}^2$$. If the strip is bent in a semicircular shape, its magnetic moment will be ________ $$\mathrm{Am}^2$$.

(given $$\pi=\frac{22}{7}$$)
پاسخ دهید
28
29
Monochromatic light of wavelength $$500 \mathrm{~nm}$$ is used in Young's double slit experiment. An interference pattern is obtained on a screen. When one of the slits is covered with a very thin glass plate (refractive index $$=1.5$$), the central maximum is shifted to a position previously occupied by the $$4^{\text {th }}$$ bright fringe. The thickness of the glass-plate is __________ $$\mu \mathrm{m}$$.
پاسخ دهید
4
30
A capacitor of reactance $$4 \sqrt{3} \Omega$$ and a resistor of resistance $$4 \Omega$$ are connected in series with an ac source of peak value $$8 \sqrt{2} \mathrm{~V}$$. The power dissipation in the circuit is __________ W.
پاسخ دهید
4