RE-NEET Physics Dual Nature of Matter & Radiation Class 12 Questions
5 questions
A beam of light falls on a metal surface such that photo-electrons are generated. If power of the light source starts to decrease linearly with time t, then variation of the photocurrent I and magnitude of the stopping potential |V| with time is best represented by :
A ray of light with wavelength λ is incident on three different photo-electric cells namely 1, 2 and 3. The threshold wavelength of these photo-electric cells are λ₁, λ₂, and λ₃, respectively and the magnitude of stopping potentials of these cells are V₁, V₂ and V₃, respectively. The relation between λ and threshold wavelengths are λ₁ < λ, λ₂ > λ and λ₃ >> λ. The correct option is:
A photon and an electron, each of 20 eV energy, move in free space. The ratio of linear momentum of electron pₑ to that of photon p_ph is: (Take speed of light = 3×10⁸ ms⁻¹, charge of electron = -1.6×10⁻¹⁹ C and mass of electron = 9×10⁻³¹ kg)
Q
If ϕ is the work function of photosensitive material in eV and light of wavelength of numerical value λ = metre, is incident on it with energy above its threshold value at an instant then the maximum kinetic energy of the photo-electron ejected by it at that instant (Take h-Planck’s constant, c-velocity of light in free space) is (in SI units):