JEE Mains Practice physics questions with solutions

Showing 1–10 of 90 questions

• NumericmediumFluid Mechanics

  A cylindrical vessel open at the top is 20 cm high and 10 cm in diameter. A circular hole whose cross-sectional area 1 cm² is cut at the centre of the bottom of the vessel. Water flows from a tube above it into the vessel at the rate 100 cm³s-1. Find the height (in cm) of water in the vessel under

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• NumericmediumNuclear physics

  Assume the Sun consists entirely of hydrogen and releases 26 MeV in the reaction 4(¹₁H) → ⁴₂He. If the solar power remains 3.9 × 10²⁶ W and the Sun's mass is 1.7 × 10³⁰ kg, the burn time is (8/3) × 10ⁿ s. Find n.

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• MCQmediumFluid Mechanics

  Statement-1: Submarine sailors are advised not to allow a submarine to rest on the ocean floor. Statement-2: The force exerted by a liquid on a submerged body may be downward.

  Options

  • Option A

    Statement-1 is true, Statement-2 is true and Statement-2 is the correct explanation of Statement-1.

  • Option B

    Statement-1 is true, Statement-2 is true but Statement-2 is not the correct explanation of Statement-1.

  • Option C

    Statement-1 is true and Statement-2 is false.

  • Option D

    Statement-1 is false and Statement-2 is true.

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• MCQeasyWave Motion

  A sound wave has a wavelength of 3.0 m. The distance from a compression center to the adjacent rarefaction center is:

  Options

  • Option A

    0.75 m

  • Option B

    1.5 m

  • Option C

    3.0 m

  • Option D

    need to know wave speed

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• MCQmediumWave Motion

  For a travelling one dimensional mechanical sinusoidal, wave, which option is incorrect;

  Options

  • Option A

    potential energy and kinetic energy of an element become maximum simultaneously.

  • Option B

    all particles oscillate with the same frequency and the same amplitude

  • Option C

    all particles may come to rest simultaneously

  • Option D

    we can find two particles, in a length equal to half of a wavelength, which have the same non-zero acceleration simultaneously.

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• MCQmediumFluid Mechanics

  A closed rectangular vessel completely filled with liquid of density ρ accelerates horizontally with a = g. Points P₁ and P₂ are separated horizontally by b and vertically by h as shown. Find P₁ - P₂. Image

  Options

  • Option A

    ρgb

  • Option B

    ρg(b+h)/2

  • Option C

    ρg(b-h)

  • Option D

    ρgh

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• MCQmediumNuclear physics

  90% of a radioactive sample is left undecayed after time t has elapsed. What percentage of the initial sample will decay in a total time 2t:

  Options

  • Option A

    20%

  • Option B

    19%

  • Option C

    40%

  • Option D

    38%

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• MCQmediumWave Motion

  A wave pulse is given by the equation y = f (x, t) = A exp (-B(x - vt)²). Given A = 1.0m, B = 1.0 m⁻² and v = + 2.0 m s⁻¹, which of the following graph shows the correct wave profile at the instant t = 1 s?

  Options

  • Option A

    
  • Option B

    
  • Option C

    
  • Option D

    

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• MCQmediumFluid Mechanics

  Statement-1: The free surface of a liquid at rest relative to a stationary container is always normal to the effective gravitational field. Statement-2: A liquid at rest cannot sustain shear stress.

  Options

  • Option A

    Statement-1 is true, Statement-2 is true and Statement-2 is the correct explanation of Statement-1.

  • Option B

    Statement-1 is true, Statement-2 is true but Statement-2 is not the correct explanation of Statement-1.

  • Option C

    Statement-1 is true and Statement-2 is false.

  • Option D

    Statement-1 is false and Statement-2 is true.

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• MCQmediumAtomic Structure and X-rays

  The wavelength of Kα X-ray of an element having atomic number Z = 11 is λ . The wavelength of Kα X-ray of another element of atomic number Z' is 4λ. Then Z' is

  Options

  • Option A

    11

  • Option B

    44

  • Option C

    6

  • Option D

    4

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