JEE Advanced physics questions with solutions

Showing 1–10 of 2483 questions

• Multi-correctmediumPhotoelectric effect and dual naturePhotoelectric Effect & Einstein's Equation

  A small perfectly absorbing photocathode is illuminated by an isotropic monochromatic point source. Initially the source has total optical power P, wavelength λ and is at distance r from the photocathode. The frequency is above threshold. The experiment is modified so that the optical power remains P, the wavelength becomes λ ÷ 2, and the source-cathode distance becomes 2r. Assume photocathode area, orientation and quantum efficiency remain unchanged. Which statements are correct?

  Select all that apply

  • Option A

    The photon arrival rate at the photocathode becomes 1 ÷ 8 of its original value

  • Option B

    The saturation current becomes 1 ÷ 8 of its original value

  • Option C

    The radiation force due purely to absorbed incident light becomes 1 ÷ 4 of its original value

  • Option D

    The stopping potential necessarily becomes exactly twice its original value

  Check answerShow answer

  JEE MainsNEETJEE Advanced

  Open question & full solution →
• ParagraphdifficultKinematics part-3 Relative motionRelative motion in 2-D and shortest distance problem

  A car is moving south at 20 m s⁻¹. A motorcyclist is moving east at 15 m s⁻¹. At a certain instant, the motorcyclist is due south of the car and is 50 m away from it.

  Sub-question 1

  The shortest distance between the motorcyclist and the car is:

  Options

  • Option A

    20 m

  • Option B

    10 m

  • Option C

    40 m

  • Option D

    30 m

  Sub-question 2

  The time after which they are closest to each other is:

  Options

  • Option A

    13 s

  • Option B

    8/3 s

  • Option C

    1/5 s

  • Option D

    8/5 s

  Check answerShow answer

  JEE MainsJEE Advanced

  Open question & full solution →
• NumericmediumWork , Power and EnergyKinetic Energy & Work-Energy Theorem

  A 1 kg block is projected upward along a 37° rough incline with speed 10 m/s. The coefficient of kinetic friction is 1/4. Take g = 10 m/s², sin37° = 3/5 and cos37° = 4/5. If the distance travelled before stopping is N/4 m, find N.

  Your answer

  Check answerShow answer

  JEE MainsNEETJEE Advanced

  Open question & full solution →
• ParagraphdifficultGeometrical opticsLaws of Refraction & Total Internal Reflection

  Light guidance in an optical fiber can be understood by considering a structure comprising of thin solid glass cylinder of refractive index n₁ surrounded by a medium of lower refractive index n₂. The light guidance in the structure takes place due to successive total internal reflections at the interface of the media n₁ and n₂ as shown in the figure. All rays with the angle of incidence i less than a particular value of iₘ are confined in the medium of refractive index n₁. The numerical aperture (NA) of the structure is defined as sin iₘ.

  

  Sub-question 1

  For two structures namely S₁ with n₁ = √45/4 and n₂ = 3/2, and S₂ with n₁ = 8/5 and n₂ = 7/5 and taking the refractive index of water to be 4/3 and that of air to be 1, the correct option(s) is (are)

  Select all that apply

  • Option A

    NA of S₁ immersed in water is the same as that of S₂ immersed in liquid of refractive index 16/(3√15).

  • Option B

    NA of S₁ immersed in liquid of refractive index 6/√15 is the same as that of S₂ immersed in water.

  • Option C

    NA of S₁ placed in air is the same as that of S₂ immersed in liquid of refractive index 4/√15.

  • Option D

    NA of S₁ placed in air is the same as that of S₂ placed in water.

  Sub-question 2

  If two structures of same cross-sectional area, but different numerical apertures NA₁ and NA₂ (NA₂ < NA₁) are joined longitudinally, the numerical aperture of the combined structure is

  Options

  • Option A

    NA₁NA₂/(NA₁ + NA₂)

  • Option B

    NA₁ + NA₂

  • Option C

    NA₁

  • Option D

    NA₂

  Check answerShow answer

  JEE Advanced

  Open question & full solution →
• NumericmediumKinematics part-3 Relative motionRelative motion in 2-D and shortest distance problem

  A mouse moves in a straight line at 3 m/s. Initially a cat is 16 m perpendicular from the mouse's line and runs at 5 m/s, always directly towards it. If capture time is N seconds, find N.

  Your answer

  Check answerShow answer

  JEE MainsNEETJEE Advanced

  Open question & full solution →
• MCQmediumThermodynamics

  Two engines A and B have source temperatures 400 K and 350 K, and sink temperatures 350 K and 300 K, respectively. Let η₁ and η₂ be the efficiencies of engines A and B. Which result is correct?

  Options

  • Option A

    η₁=12.5%; η₂=14.3% (B is more efficient)

  • Option B

    η₁=14.3%; η₂=12.5%

  • Option C

    η₁=η₂=12.5%

  • Option D

    η₁=η₂=14.3%

  Check answerShow answer

  JEE Advanced

  Open question & full solution →
• MCQmediumAtomic Structure and X-raysAtomic Structure & Bohr's Atomic Model

  A hydrogen atom is initially in its ground state. An external agent supplies just enough energy to place the electron directly in the third Bohr orbit without ionising the atom. How much energy must be supplied?

  Options

  • Option A

    10.2 eV

  • Option B

    12.09 eV

  • Option C

    12.75 eV

  • Option D

    13.6 eV

  Check answerShow answer

  JEE MainsNEETJEE Advanced

  Open question & full solution →
• NumericeasyCenter of maas , Momentum and CollisionCentre of Mass & Its Calculation

  A thin circular disc of radius R has surface mass density σ(r) = σ₀r/R, where r is the distance from its geometrical centre. If the distance of its centre of mass from the geometrical centre is NR, find N.

  Your answer

  Check answerShow answer

  JEE MainsNEETJEE Advanced

  Open question & full solution →
• MCQeasyCircular MotionKinematics of Circular Motion

  At an instant, a particle moving on a circle has tangential acceleration aₜ = 3 m/s² and radial acceleration $a_c$ = 4 m/s². The angle φ made by the net acceleration with the inward radial direction is:

  Options

  • Option A

    tan⁻¹($\frac{3}{4}$)

  • Option B

    tan⁻¹(4/3)

  • Option C

    45°

  • Option D

    90°

  Check answerShow answer

  JEE MainsNEETJEE Advanced

  Open question & full solution →
• MCQmediumWave MotionBeats, Loudness, Pitch and Characteristics of Sound

  A standard tuning fork has frequency 400 Hz. An unknown fork produces 7 beats per second with it. The unknown fork is filed in such a way that its frequency increases by exactly 10 Hz, after which the two forks produce 3 beats per second. What was the original frequency of the unknown fork?

  Options

  • Option A

    393 Hz

  • Option B

    397 Hz

  • Option C

    403 Hz

  • Option D

    407 Hz

  Check answerShow answer

  JEE MainsNEETJEE Advanced

  Open question & full solution →