JEE MAIN - Physics (2024 - 5th April Morning Shift)
1
A body of mass $$50 \mathrm{~kg}$$ is lifted to a height of $$20 \mathrm{~m}$$ from the ground in the two different ways as shown in the figures. The ratio of work done against the gravity in both the respective cases, will be :
Answer
(C)
$$1: 1$$
2
If $$\mathrm{G}$$ be the gravitational constant and $$\mathrm{u}$$ be the energy density then which of the following quantity have the dimensions as that of the $$\sqrt{\mathrm{uG}}$$ :
Answer
(D)
Force per unit mass
3
An alternating voltage of amplitude $$40 \mathrm{~V}$$ and frequency $$4 \mathrm{~kHz}$$ is applied directly across the capacitor of $$12 \mu \mathrm{F}$$. The maximum displacement current between the plates of the capacitor is nearly :
Answer
(D)
12 A
4
Ratio of radius of gyration of a hollow sphere to that of a solid cylinder of equal mass, for moment of Inertia about their diameter axis $$A B$$ as shown in figure is $$\sqrt{8 / x}$$. The value of $$x$$ is :
Answer
(C)
67
5
In hydrogen like system the ratio of coulombian force and gravitational force between an electron and a proton is in the order of :
Answer
(B)
1039
6
A simple pendulum doing small oscillations at a place $$R$$ height above earth surface has time period of $$T_1=4 \mathrm{~s}$$. $$\mathrm{T}_2$$ would be it's time period if it is brought to a point which is at a height $$2 \mathrm{R}$$ from earth surface. Choose the correct relation [$$\mathrm{R}=$$ radius of earth] :
Answer
(A)
$$3 \mathrm{~T}_1=2 \mathrm{~T}_2$$
7
Match List I with List II :
LIST I
LIST II
A.
Kinetic energy of planet
I.
$$ -\mathrm{GMm} / \mathrm{a} $$
B.
Gravitation Potential energy of sun-planet system
II.
$$ \mathrm{GMm} / 2 \mathrm{a} $$
C.
Total mechanical energy of planet
III.
$$ \frac{\mathrm{Gm}}{\mathrm{r}} $$
D.
Escape energy at the surface of planet for unit mass object
IV.
$$ -\mathrm{GMm} / 2 \mathrm{a} $$
(Where $$\mathrm{a}=$$ radius of planet orbit, $$\mathrm{r}=$$ radius of planet, $$\mathrm{M}=$$ mass of Sun, $$\mathrm{m}=$$ mass of planet)
Choose the correct answer from the options given below :
Answer
(A)
(A)-(II), (B)-(I), (C)-(IV), (D)-(III)
8
The heat absorbed by a system in going through the given cyclic process is :
Answer
(A)
61.6 J
9
In the given figure $$\mathrm{R}_1=10 \Omega, \mathrm{R}_2=8 \Omega, \mathrm{R}_3=4 \Omega$$ and $$\mathrm{R}_4=8 \Omega$$. Battery is ideal with emf $$12 \mathrm{~V}$$. Equivalent resistant of the circuit and current supplied by battery are respectively :
Answer
(D)
$$12 \Omega$$ and $$1 \mathrm{~A}$$
10
Two conducting circular loops A and B are placed in the same plane with their centres coinciding as shown in figure. The mutual inductance between them is:
If the collision frequency of hydrogen molecules in a closed chamber at $$27^{\circ} \mathrm{C}$$ is $$\mathrm{Z}$$, then the collision frequency of the same system at $$127^{\circ} \mathrm{C}$$ is :
Answer
(B)
$$\frac{2}{\sqrt{3}} \mathrm{Z}$$
12
Given below are two statements :
Statement I : Figure shows the variation of stopping potential with frequency $$(v)$$ for the two photosensitive materials $$M_1$$ and $$M_2$$. The slope gives value of $$\frac{h}{e}$$, where $$h$$ is Planck's constant, e is the charge of electron.
Statement II : $$\mathrm{M}_2$$ will emit photoelectrons of greater kinetic energy for the incident radiation having same frequency.
In the light of the above statements, choose the most appropriate answer from the options given below.
Answer
(A)
Statement I is correct and Statement II is incorrect
13
Following gates section is connected in a complete suitable circuit.
For which of the following combination, bulb will glow (ON) :
Statement I : When a capillary tube is dipped into a liquid, the liquid neither rises nor falls in the capillary. The contact angle may be $$0^{\circ}$$.
Statement II : The contact angle between a solid and a liquid is a property of the material of the solid and liquid as well.
In the light of the above statement, choose the correct answer from the options given below.
Answer
(B)
Statement I is false but Statement II is true
15
Light emerges out of a convex lens when a source of light kept at its focus. The shape of wavefront of the light is :
Answer
(C)
plane
16
An electron rotates in a circle around a nucleus having positive charge $$\mathrm{Ze}$$. Correct relation between total energy (E) of electron to its potential energy (U) is :
Answer
(C)
$$2 \mathrm{E}=\mathrm{U}$$
17
Time periods of oscillation of the same simple pendulum measured using four different measuring clocks were recorded as $$4.62 \mathrm{~s}, 4.632 \mathrm{~s}, 4.6 \mathrm{~s}$$ and $$4.64 \mathrm{~s}$$. The arithmetic mean of these readings in correct significant figure is :
Answer
(B)
4.6 s
18
The angle between vector $$\vec{Q}$$ and the resultant of $$(2 \vec{Q}+2 \vec{P})$$ and $$(2 \vec{Q}-2 \vec{P})$$ is :
Answer
(B)
0$$^\circ$$
19
In a co-axial straight cable, the central conductor and the outer conductor carry equal currents in opposite directions. The magnetic field is zero :
Answer
(B)
outside the cable
20
A wooden block of mass $$5 \mathrm{~kg}$$ rests on a soft horizontal floor. When an iron cylinder of mass $$25 \mathrm{~kg}$$ is placed on the top of the block, the floor yields and the block and the cylinder together go down with an acceleration of $$0.1 \mathrm{~ms}^{-2}$$. The action force of the system on the floor is equal to :
Answer
(B)
291 N
21
The electric field between the two parallel plates of a capacitor of $$1.5 \mu \mathrm{F}$$ capacitance drops to one third of its initial value in $$6.6 \mu \mathrm{s}$$ when the plates are connected by a thin wire. The resistance of this wire is ________ $$\Omega$$. (Given, $$\log 3=1.1$$)
Answer
4
22
If three helium nuclei combine to form a carbon nucleus then the energy released in this reaction is
________ $$\times 10^{-2} \mathrm{~MeV}$$. (Given $$1 \mathrm{u}=931 \mathrm{~MeV} / \mathrm{c}^2$$, atomic mass of helium $$=4.002603 \mathrm{u}$$)
Answer
727
23
Three blocks $$\mathrm{M_1, M_2, M_3}$$ having masses $$4 \mathrm{~kg}, 6 \mathrm{~kg}$$ and $$10 \mathrm{~kg}$$ respectively are hanging from a smooth pully using rope 1, 2 and 3 as shown in figure. The tension in the rope $$\mathrm{1, T_1}$$ when they are moving upward with acceleration of $$2 \mathrm{~ms}^{-2}$$ is __________ $$\mathrm{N}$$ (if $$\mathrm{g}=10 \mathrm{~m} / \mathrm{s}^2$$).
Answer
240
24
Three capacitors of capacitances $$25 \mu \mathrm{F}, 30 \mu \mathrm{F}$$ and $$45 \mu \mathrm{F}$$ are connected in parallel to a supply of $$100 \mathrm{~V}$$. Energy stored in the above combination is E. When these capacitors are connected in series to the same supply, the stored energy is $$\frac{9}{x} \mathrm{E}$$. The value of $$x$$ is _________.
Answer
86
25
In the experiment to determine the galvanometer resistance by half-deflection method, the plot of $$1 / \theta$$ vs the resistance (R) of the resistance box is shown in the figure. The figure of merit of the galvanometer is _________ $$\times 10^{-1} \mathrm{~A} /$$ division. [The source has emf $$2 \mathrm{~V}$$]
Answer
5
26
The density and breaking stress of a wire are $$6 \times 10^4 \mathrm{~kg} / \mathrm{m}^3$$ and $$1.2 \times 10^8 \mathrm{~N} / \mathrm{m}^2$$ respectively. The wire is suspended from a rigid support on a planet where acceleration due to gravity is $$\frac{1}{3}^{\text {rd }}$$ of the value on the surface of earth. The maximum length of the wire with breaking is _______ $$\mathrm{m}$$ (take, $$\mathrm{g}=10 \mathrm{~m} / \mathrm{s}^2$$).
Answer
600
27
An ac source is connected in given series LCR circuit. The rms potential difference across the capacitor of $$20 \mu \mathrm{F}$$ is __________ V.
Answer
50
28
A body moves on a frictionless plane starting from rest. If $$\mathrm{S_n}$$ is distance moved between $$\mathrm{t=n-1}$$ and $$\mathrm{t}=\mathrm{n}$$ and $$\mathrm{S}_{\mathrm{n}-1}$$ is distance moved between $$\mathrm{t}=\mathrm{n}-2$$ and $$\mathrm{t}=\mathrm{n}-1$$, then the ratio $$\frac{\mathrm{S}_{\mathrm{n}-1}}{\mathrm{~S}_{\mathrm{n}}}$$ is $$\left(1-\frac{2}{x}\right)$$ for $$\mathrm{n}=10$$. The value of $$x$$ is __________.
Answer
19
29
In Young's double slit experiment, carried out with light of wavelength $$5000~\mathop A\limits^o$$, the distance between the slits is $$0.3 \mathrm{~mm}$$ and the screen is at $$200 \mathrm{~cm}$$ from the slits. The central maximum is at $$x=0 \mathrm{~cm}$$. The value of $$x$$ for third maxima is __________ $$\mathrm{mm}$$.
Answer
10
30
A 2A current carrying straight metal wire of resistance $$1 \Omega$$, resistivity $$2 \times 10^{-6} \Omega \mathrm{m}$$, area of cross-section $$10 \mathrm{~mm}^2$$ and mass $$500 \mathrm{~g}$$ is suspended horizontally in mid air by applying a uniform magnetic field $$\vec{B}$$. The magnitude of B is ________ $$\times 10^{-1} \mathrm{~T}$$ (given, $$\mathrm{g}=10 \mathrm{~m} / \mathrm{s}^2$$).