JEE Mains 2025 29 Jan Evening Shift physics questions with solutions

Showing 1–10 of 20 questions

• MCQmediumWave Opticsinterferece of light and huygen principle

  A soap film on a ring of radius 3 cm evaporates. Light of wavelength 580 nm gives minimum transmission every 12 s. Re$fractive$ index is 1.45. The rate of evaporation is:

  Options

  • Option A

    1.5π×10⁻¹³ m³/s

  • Option B

    15π×10⁻¹³ m³/s

  • Option C

    3π×10⁻¹³ m³/s

  • Option D

    3π×10⁻¹² m³/s

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• MCQmediumMagnetism and matterpole stength ,magnetic moment and magnetic field due to magnet

  For the bar magnet geometry shown, d=10 units and half-length l=10 units. If percentage uncertainty in d is 1%, the percentage uncertainty in magnetic field at point P is:

  

  Options

  • Option A

    2%

  • Option B

    3%

  • Option C

    1.5%

  • Option D

    0.5%

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• MCQmediumCapacitorparallel plate capacitor ,cylindrical capacitor and spherical capacitor

  A 1 μF parallel-plate capacitor is charged to 20 V. Plate separation is 10 μm. The charge density on the plates is:

  Options

  • Option A

    17.7 nC/m²

  • Option B

    17.7 μC/m²

  • Option C

    8.85 nC/m²

  • Option D

    4.42 μC/m²

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• MCQmediumMagnetic effect of currentbiot savart law and magnetic field due to straight conductor ,arc and ring

  For the current-carrying arrangement shown in the original figure, the magnetic field at centre O is:

  

  Options

  • Option A

    [μ₀I(3π+2)/(8πa)] k̂

  • Option B

    -[μ₀I(3π+2)/(8πa)] k̂

  • Option C

    [μ₀I(3π-2)/(8πa)] k̂

  • Option D

    -[μ₀I(3π-2)/(8πa)] k̂

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• MCQeasyCapacitorparallel plate capacitor ,cylindrical capacitor and spherical capacitor

  The energy density between the plates of a parallel-plate capacitor having potential difference V and plate separation d is:

  Options

  • Option A

    ε₀V²/(2d²)

  • Option B

    ε₀Vd²/2

  • Option C

    ε₀AV²/(2d)

  • Option D

    ε₀AV²/(2d²)

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• MCQmediumMagnetic effect of currentbiot savart law and magnetic field due to straight conductor ,arc and ring

  An equilateral triangular wire frame of side l carries current i. The magnetic field at its centroid is:

  Options

  • Option A

    3μ₀i/(4πl)

  • Option B

    3μ₀i/(πl)

  • Option C

    9μ₀i/(2πl)

  • Option D

    μ₀i/(πl)

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• IntegermediumElectromagnetic Inductionfaradays law and question based on it

  A conducting rod slides with constant velocity on two rails making an angle 60° in a uniform magnetic field. If the motional emf varies as E=ctⁿ, the value of n is:

  

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• MCQmediumsemiconductorapplication of diode and zener breakdown

  For the diode circuit shown in the original question, with V=V₀sinωt and negligible threshold voltage, the voltage $V_AB$ is:

  

  Options

  • Option A

    
  • Option B

    
  • Option C

    
  • Option D

    

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• MCQmediumNewtons law of motion and Frictionnewton second law and problem based on it

  A balloon system of mass m moves upward with acceleration a. What mass x must be removed so that its upward acceleration becomes 3a? Neglect the volume of the removed mass.

  

  Options

  • Option A

    2ma/(3a+g)

  • Option B

    2ma/(2a+g)

  • Option C

    ma/(3a+g)

  • Option D

    ma/(g-3a)

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• IntegereasyKinematics Part-1 (one dimension)Ghraphical problem of kinematics

  From the velocity-time graph in the original paper, velocity remains positive from t=0 to 4 s and the area under the graph is 30 m. The distance travelled is:

  

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