Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
JEE MainPhysicsDual Nature of Matter

Two monochromatic light sources A and B have the same power. When light from these sources is separately used to illuminate a photosensitive surface having a work function of 2.5 eV , the stopping potentials are found to be 1.5 V and 3.5 V respectively. The ratio of the number of photons emitted per second by source A to that by source B is :

Options

  1. A2:3
  2. B3:7
  3. C3:2
  4. D7:3

Correct answer

C. 3:2

Step-by-step solution

From Einstein's photoelectric equation, the energy of an incident photon is given by E = + eV_s , where is the work function and V_s is the stopping potential. For source A, the photon energy is: E_A = 2.5 eV + 1.5 eV = 4.0 eV For source B, the photon energy is: E_B = 2.5 eV + 3.5 eV = 6.0 eV The power of a light source is related to the number of photons emitted per second n and the energy of each photon E by the relation P = nE . Since both sources have the same power ( P_A = P_B ): n_A E_A = n_B E_B n_A n_B = E_

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