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JEE Main 2024 Jan 31 Shift 1Physics

30 questions · 30 with the official NTA answer

Q31JEE Main 2024 Jan 31 Shift 1Units and MeasurementsEasy

A force is represented by F=ax2+bt12F = ax^2 + bt^{\frac{1}{2}}

where xx = distance and tt = time. The dimensions of b2/ab^2/a are:

  1. A

    [MLT2][\mathrm{MLT^{-2}}]

  2. B

    [ML1T1][\mathrm{ML^{-1}T^{-1}}]

  3. C

    [ML2T3][\mathrm{ML^{2}T^{-3}}]

  4. D

    [ML3T3][\mathrm{ML^{3}T^{-3}}]

Show answer

Correct option: D

Q32JEE Main 2024 Jan 31 Shift 1KinematicsMedium

The relation between time t't' and distance x'x' is t=αx2+βxt = \alpha x^2 + \beta x, where α\alpha and β\beta are constants. The relation between acceleration (a)(a) and velocity (v)(v) is :

  1. A

    a=2αv3a = -2\alpha v^3

  2. B

    a=3αv2a = -3\alpha v^2

  3. C

    a=4αv4a = -4\alpha v^4

  4. D

    a=5αv5a = -5\alpha v^5

Show answer

Correct option: A

Q33JEE Main 2024 Jan 31 Shift 1Laws of MotionEasy

A coin is placed on a disc. The coefficient of friction between the coin and the disc is μ\mu. If the distance of the coin from the center of the disc is rr, the maximum angular velocity which can be given to the disc, so that the coin does not slip away, is :

  1. A

    μgr\frac{\mu g}{r}

  2. B

    μgr\sqrt{\frac{\mu g}{r}}

  3. C

    rμg\sqrt{\frac{r}{\mu g}}

  4. D

    μrg\frac{\mu}{\sqrt{rg}}

Show answer

Correct option: B

Q34JEE Main 2024 Jan 31 Shift 1Laws of MotionMedium

In the given arrangement of a doubly inclined plane two blocks of masses MM and mm are placed. The blocks are connected by a light string passing over an ideal pulley as shown. The coefficient of friction between the surface of the plane and the blocks is 0.25. The value of mm, for which M=10M = 10 kg will move down with an acceleration of 2 m/s22\ \mathrm{m/s^2}, is: (take g=10 m/s2g = 10\ \mathrm{m/s^2} and tan37°=3/4\tan 37° = 3/4)

Figure — described from the original paper

double inclined plane with block M on the 53° incline and block m on the 37° incline, connected by a string over a pulley at the apex

  1. A

    4.5 kg

  2. B

    9 kg

  3. C

    2.25 kg

  4. D

    6.5 kg

Show answer

Correct option: A

Q35JEE Main 2024 Jan 31 Shift 1Work, Energy and PowerEasy

An artillery piece of mass M1M_1 fires a shell of mass M2M_2 horizontally. Instantaneously after the firing, the ratio of kinetic energy of the artillery and that of the shell is:

  1. A

    M1M2\frac{M_1}{M_2}

  2. B

    M2M1\frac{M_2}{M_1}

  3. C

    M1/(M1+M2)M_1 / (M_1 + M_2)

  4. D

    M2/(M1+M2)M_2 / (M_1 + M_2)

Show answer

Correct option: B

Q36JEE Main 2024 Jan 31 Shift 1GravitationMedium

Four identical particles of mass mm are kept at the four corners of a square. If the gravitational force exerted on one of the masses by the other masses is (22+132)Gm2L2\left(\frac{2\sqrt{2}+1}{32}\right)\frac{Gm^2}{L^2}, the length of the sides of the square is

  1. A

    L2\frac{L}{2}

  2. B

    4L4L

  3. C

    2L2L

  4. D

    3L3L

Show answer

Correct option: B

Q37JEE Main 2024 Jan 31 Shift 1Properties of Solids and LiquidsEasy

A small steel ball is dropped into a long cylinder containing glycerine. Which one of the following is the correct representation of the velocity time graph for the transit of the ball?

  1. A
    Figure — described from the original paper

    v–t graph, straight line rising linearly from origin

  2. B
    Figure — described from the original paper

    v–t graph, velocity rises linearly then falls linearly to zero (triangular shape)

  3. C
    Figure — described from the original paper

    v–t graph, velocity rises steeply then saturates to a constant terminal value

  4. D
    Figure — described from the original paper

    v–t graph, velocity constant initially then decreases linearly

Show answer

Correct option: C

Q38JEE Main 2024 Jan 31 Shift 1ThermodynamicsEasy

The given figure represents two isobaric processes for the same mass of an ideal gas, then

Figure — described from the original paper

V–T graph with two straight lines from origin O, line P2P_2 steeper (above) line P1P_1

  1. A

    P1>P2P_1 > P_2

  2. B

    P2>P1P_2 > P_1

  3. C

    P1=P2P_1 = P_2

  4. D

    P2P1P_2 \geq P_1

Show answer

Correct option: A

Q39JEE Main 2024 Jan 31 Shift 1Kinetic Theory of GasesEasy

The parameter that remains the same for molecules of all gases at a given temperature is :

  1. A

    mass

  2. B

    speed

  3. C

    momentum

  4. D

    kinetic energy

Show answer

Correct option: D

Q40JEE Main 2024 Jan 31 Shift 1ElectrostaticsMedium

Two charges qq and 3q3q are separated by a distance r'r' in air. At a distance xx from charge qq, the resultant electric field is zero. The value of xx is :

  1. A

    r(1+3)r\left(1+\sqrt{3}\right)

  2. B

    (1+3)r\frac{\left(1+\sqrt{3}\right)}{r}

  3. C

    r(1+3)\frac{r}{\left(1+\sqrt{3}\right)}

  4. D

    r3(1+3)\frac{r}{3\left(1+\sqrt{3}\right)}

Show answer

Correct option: C

Q41JEE Main 2024 Jan 31 Shift 1Current ElectricityMedium

Two conductors have the same resistances at 0°C0°\mathrm{C} but their temperature coefficients of resistance are α1\alpha_1 and α2\alpha_2. The respective temperature coefficients for their series and parallel combinations are :

  1. A

    α1+α22, α1+α22\frac{\alpha_1+\alpha_2}{2},\ \frac{\alpha_1+\alpha_2}{2}

  2. B

    α1+α22, α1+α2\frac{\alpha_1+\alpha_2}{2},\ \alpha_1+\alpha_2

  3. C

    α1+α2, α1+α22\alpha_1+\alpha_2,\ \frac{\alpha_1+\alpha_2}{2}

  4. D

    α1+α2, α1α2α1+α2\alpha_1+\alpha_2,\ \frac{\alpha_1 \alpha_2}{\alpha_1+\alpha_2}

Show answer

Correct option: A

Q42JEE Main 2024 Jan 31 Shift 1Magnetic Effects of Current and MagnetismMedium

A rigid wire consists of a semicircular portion of radius RR and two straight sections. The wire is partially immerged in a perpendicular magnetic field B=B0j^B = B_0\,\hat{j} as shown in figure. The magnetic force on the wire if it has a current ii is:

Figure — described from the original paper

U-shaped wire with semicircular top of radius R inside a region of magnetic field pointing out of the page (dots), with x–y axes shown; the two straight sections extend downward out of the field region

  1. A

    2iBRj^2iBR\,\hat{j}

  2. B

    2iBRj^-2iBR\,\hat{j}

  3. C

    iBRj^iBR\,\hat{j}

  4. D

    iBRj^-iBR\,\hat{j}

Show answer

Correct option: B

Q43JEE Main 2024 Jan 31 Shift 1Electromagnetic Induction and Alternating CurrentsMedium

A coil is places perpendicular to a magnetic field of 5000 T. When the field is changed to 3000 T in 2 s, an induced emf of 22 V is produced in the coil. If the diameter of the coil is 0.02 m, then the number of turns in the coil is:

  1. A

    7

  2. B

    140

  3. C

    35

  4. D

    70

Show answer

Correct option: D

Q44JEE Main 2024 Jan 31 Shift 1Electromagnetic WavesMedium

In a plane EM wave, the electric field oscillates sinusoidally at a frequency of 5×10105 \times 10^{10} Hz and an amplitude of 50 Vm150\ \mathrm{Vm^{-1}}. The total average energy density of the electromagnetic field of the wave is : [Use ε0=8.85×1012 C2/Nm2\varepsilon_0 = 8.85 \times 10^{-12}\ \mathrm{C^2/Nm^2}]

  1. A

    1.106×108 Jm31.106 \times 10^{-8}\ \mathrm{Jm^{-3}}

  2. B

    2.212×1010 Jm32.212 \times 10^{-10}\ \mathrm{Jm^{-3}}

  3. C

    2.212×108 Jm32.212 \times 10^{-8}\ \mathrm{Jm^{-3}}

  4. D

    4.425×108 Jm34.425 \times 10^{-8}\ \mathrm{Jm^{-3}}

Show answer

Correct option: A

Q45JEE Main 2024 Jan 31 Shift 1Ray OpticsMedium

The refractive index of a prism with apex angle AA is cotA/2\cot A/2. The angle of minimum deviation is :

  1. A

    δm=180°2A\delta_m = 180° - 2A

  2. B

    δm=180°3A\delta_m = 180° - 3A

  3. C

    δm=180°4A\delta_m = 180° - 4A

  4. D

    δm=180°A\delta_m = 180° - A

Show answer

Correct option: A

Q46JEE Main 2024 Jan 31 Shift 1Dual Nature of Matter and RadiationMedium

When a metal surface is illuminated by light of wavelength λ\lambda, the stopping potential is 8V. When the same surface is illuminated by light of wavelength 3λ3\lambda, stopping potential is 2V. The threshold wavelength for this surface is:

  1. A

    4.5λ4.5\lambda

  2. B

    3λ3\lambda

  3. C

    5λ5\lambda

  4. D

    9λ9\lambda

Show answer

Correct option: D

Q47JEE Main 2024 Jan 31 Shift 1Atoms and NucleiMedium

If the wavelength of the first member of Lyman series of hydrogen is λ\lambda. The wavelength of the second member will be

  1. A

    2732λ\frac{27}{32}\lambda

  2. B

    3227λ\frac{32}{27}\lambda

  3. C

    275λ\frac{27}{5}\lambda

  4. D

    527λ\frac{5}{27}\lambda

Show answer

Correct option: A

Q48JEE Main 2024 Jan 31 Shift 1Electronic DevicesMedium

Identify the logic operation performed by the given circuit.

Figure — described from the original paper

logic circuit — inputs A and B each pass through a NOT gate (inverter), whose outputs feed a NAND gate giving output Y

  1. A

    AND

  2. B

    OR

  3. C

    NAND

  4. D

    NOR

Show answer

Correct option: B

Q49JEE Main 2024 Jan 31 Shift 1WavesMedium

The fundamental frequency of a closed organ pipe is equal to the first overtone frequency of an open organ pipe. If length of the open pipe is 60 cm, the length of the closed pipe will be:

  1. A

    60 cm

  2. B

    45 cm

  3. C

    30 cm

  4. D

    15 cm

Show answer

Correct option: D

Q50JEE Main 2024 Jan 31 Shift 1Units and MeasurementsEasy

If the percentage errors in measuring the length and the diameter of a wire are 0.1% each. The percentage error in measuring its resistance will be:

  1. A

    0.1%

  2. B

    0.2%

  3. C

    0.3%

  4. D

    0.144%

Show answer

Correct option: C

Q51JEE Main 2024 Jan 31 Shift 1KinematicsMediumNumerical

A body starts falling freely from height HH hits an inclined plane in its path at height hh. As a result of this perfectly elastic impact, the direction of the velocity of the body becomes horizontal. The value of Hh\frac{H}{h} for which the body will take the maximum time to reach the ground is ________.

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Answer: 2

Q52JEE Main 2024 Jan 31 Shift 1Rotational MotionMediumNumerical

A solid circular disc of mass 50 kg rolls along a horizontal floor so that its center of mass has a speed of 0.4 m/s. The absolute value of work done on the disc to stop it is __________ J.

Show answer

Answer: 6

Q53JEE Main 2024 Jan 31 Shift 1Properties of Solids and LiquidsEasyNumerical

The depth below the surface of sea to which a rubber ball be taken so as to decrease its volume by 0.02% is _______ mm.

(Take density of sea water =103 kgm3= 10^3\ \mathrm{kgm^{-3}}, Bulk modulus of rubber =9×108 Nm2= 9 \times 10^8\ \mathrm{Nm^{-2}}, and g=10 ms2g = 10\ \mathrm{ms^{-2}})

Show answer

Answer: 18

Q54JEE Main 2024 Jan 31 Shift 1OscillationsMediumNumerical

A particle performs simple harmonic motion with amplitude AA. Its speed is increased to three times at an instant when its displacement is 2A3\frac{2A}{3}. The new amplitude of motion is nA3\frac{nA}{3}. The value of nn is ________.

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Answer: 7

Q55JEE Main 2024 Jan 31 Shift 1ElectrostaticsMediumNumerical

A parallel plate capacitor with plate separation 5 mm is charged up by a battery. It is found that on introducing a dielectric sheet of thickness 2 mm , while keeping the battery connections intact, the capacitor draws 25% more charge from the battery than before. The dielectric constant of the sheet is ________.

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Answer: 2

Q56JEE Main 2024 Jan 31 Shift 1Current ElectricityMediumNumerical

Equivalent resistance of the following network is ________ Ω\Omega.

Figure — described from the original paper

resistor network between terminals A and B — three parallel branches (R1R_1 6 Ω\Omega shown with R2R_2, R3R_3 2 Ω\Omega, and R5R_5 3 Ω\Omega with R6R_6 3 Ω\Omega) linked by series resistors of 2 Ω\Omega (R2R_2 top-left) and 2 Ω\Omega (R4R_4 top-right)

Show answer

Answer: 1

Q57JEE Main 2024 Jan 31 Shift 1Magnetic Effects of Current and MagnetismMediumNumerical

An electron moves through a uniform magnetic field B=B0i^+2B0j^ T\vec{B} = B_0\,\hat{i} + 2B_0\,\hat{j}\ T. At a particular instant of time, the velocity of electron is u=3i^+5j^ m/s\vec{u} = 3\hat{i} + 5\hat{j}\ \mathrm{m/s}. If the magnetic force acting on electron is F=5ek^ N\vec{F} = 5e\,\hat{k}\ N, where ee is the charge of electron, then the value of B0B_0 is ________ TT.

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Answer: 5

Q58JEE Main 2024 Jan 31 Shift 1Electromagnetic Induction and Alternating CurrentsHardNumerical

A small square loop of wire of side ll is placed inside a large square loop of wire of side LL (L=l2)(L = l^2). The loops are coplanar and their centers coincide. The value of the mutual inductance of the system is x×107 H\sqrt{x} \times 10^{-7}\ H, where x=x = ______.

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Answer: 128

Q59JEE Main 2024 Jan 31 Shift 1Wave OpticsMediumNumerical

Two waves of intensity ratio 1:9 cross each other at a point. The resultant intensities at that point, when (a) Waves are incoherent is I1I_1 (b) Waves are coherent is I2I_2 and differ in phase by 60°60°. If I1I2=10x\frac{I_1}{I_2} = \frac{10}{x} then x=x = ______.

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Answer: 13

Q60JEE Main 2024 Jan 31 Shift 1Atoms and NucleiMediumNumerical

The mass defect in a particular reaction is 0.4g. The amount of energy liberated is n×107n \times 10^7 kWh, where n=n = ______.

(speed of light =3×108= 3 \times 10^8 m/s)

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Answer: 1