Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
JEE Main201910 Apr 2019Evening ShiftPhysicsDual Nature of MatterActual

Light is incident normally on a completely absorbing surface with an energy flux of 25 W c m - 2 . If the surface has an area of 25 c m 2 , the momentum transferred to the surface in 40   min time duration will be:

Options

  1. A6.3 × 10 - 4 N s
  2. B5.0 × 10 - 3 N s
  3. C3.5 × 10 - 6 N s
  4. D1.4 × 10 - 6 N s

Correct answer

B. 5.0 × 10 - 3 N s

Step-by-step solution

The power of the incident light is P = 25    W   c m - 2 × 25   c m 2 = 625   W Energy incident per second, E = h c λ = 625   J Momentum incident per second, p = E c = h λ = 625 c ∴ Total momentum transferred to the surface = 625 c × 40 × 60 = 5 × 10 - 3   N   s

Practice Dual Nature of Matter on Quantrex Academy →

More from Dual Nature of Matter

K₁ and K₂ be the maximum kinetic energies of photoelectrons emitted from a surface of a given material for the light of wavelength ₁ and ₂ , respectively. If ₁=2 ₂ then the work fu 2026The de Broglie wavelength for an electron accelerated through the potential difference of V₁ volt is ₁ . When the potential difference is changed to V₂ volt, the associated de Brog 2026Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): The electromagnetic wave exerts pressure on the surface on 2026An electron is travelling with a velocity v in free space and when it enters a medium, its velocity is reduced by 20 % . The de Broglie wavelength of electron in the medium is ₀ , 2026An electron of mass m is moving in an electric field E = -2E₀ i ( E₀ = constant > 0 ), with an initial velocity V = v₀ i ( v₀ = constant > 0 ). If ₀ = h 4mv₀ , its de Broglie wavel 2026Light source having wavelength 331 nm is used to generate photo-electrons whose stopping potential is 0.2 V. The work function of the used metal in the experiment is 10⁻¹⁹ J. The v 2026Match the List-I with List-II List-I List-II A. Planck's constant I. ML^2T⁻² B. Stopping potential II. T⁻¹ C. Work function III. ML^2T⁻¹ D. Threshold frequency IV. ML^2T⁻³A⁻¹ Choos 2026The de Broglie wavelength associated with an electron accelerated through a potential difference V is _e and the de Broglie wavelength associated with a proton accelerated through 2026 Full Dual Nature of Matter list All JEE Main PYQs