Related InterviewSolutions

• When a metal surface is illuminated by a monochromatic light of wave-length `lambda`, then the potential difference required to stop the ejection of electrons is `3V`. When the same surface is illuminated by the light of wavelength `2lambda`, then the potential difference required to stop the ejection of electrons is `V`. Then for photoelectric effect, the threshold wavelength for the metal surface will beA. `6lambda`B. `4lambda//3`C. `4lambda`D. `8lambda`
• Which of the following is dependent on the intensity of incident radiation in a photoelectric experimentA. work function of the surfaceB. amount of photoelectric currentC. stopping potentialD. maximum kinetic energy
• A radiation of wavelength 200nm is propagating in the form of a parallel surface. The intensity of the beam is 5mW and its cross-sectional area is 1.0`mm^(2)`. Find the pressure exerted by radiation on the metallic surface if the radiation is completely reflected.
• The frequency and intensity of a light source are both doubled. Consider the following statements A. The saturation photocurrent remains almost the same B. The maximum kinetic energy of the photoelectrons is doubleA. Both `(i)` and `(ii)` are trueB. `(i)` is true but `(ii)` is falseC. `(i)` is false but `(ii)` is trueD. Both `(i)` and `(ii)` are false
• A laser used to weld detached retinas emits light with a wavelength of 652 nm in pulses that are 20.0ms in duration. The average power during each pulse is 0.6 W. then,A. `7.5xx10^(15) eV,2.7 eV`B. `6.5xx10^(16) eV,2.9 eV`C. `6.5xx10^(16) eV,2.7 eV`D. `7.5xx10^(16) eV,1.9 eV`
• A particle of mass m is projected form ground with velocity u making angle `theta` with the vertical. The de Broglie wavelength of the particle at the highest point isA. `oo`B. `h/("mu" sin theta)`C. `h/("mu" cos theta)`D. `h/"mu" `
• Two initially uncharged concentric than conducting spherical shells of radius `a` and `2a` are as shown and the inner shell is grounded. The work function of outer shell is `phi_(0)`.At time `t=0`, a continuous parallel beam of monochromatic radiation of cross-section area `A` and intensity `I` is incident on outer shell.The energy of each photon is `hv` such that `hv gt phi_(0)` Assuming for each incident photon one photoelectron is ejected, answer the following questions. The time after `t=0`, at which charge on outer sphere becomes constant. A. `(hupsilon-phi_(0))/e`B. `(hupsilon-phi_(0))/(2e)`C. `2/3(hupsilon-phi_(0))/e`D. None of these
• A particle moves in a closed orbit around the origin, due to a force which is directed towards the origin. The de-broglie wavelength of the particles varies cyclically between two values `lambda_(1), lambda_(2) with lambda_(1)gtlambda_(2)`. Which of the following statements are true?A. The particle could be moving in a circular orbit with origin as centreB. The particle could be moving in an elliptic orbit with origin as its focusC. When the de Broglie wave length is `lambda_(1)` the particle is nearer the origin that when its value is `lambda_(2)`D. When the de Broglie wavelength is `lambda_(2)` the particle is nearer the origin that when its value is `lambda_(1)`
• The maximum K.E. of photoelectrons ejected from a photometer when it is irradiated with radiation of a wavelength 400nm is 1eV. If the threshold energy of the surface is 1.9 eV,A. The maximum `K.E`. Of photo electrons when it is irradiated with `500nm` photons will be `0.42 eV`B. The maximum `K.E`. In case `(a)` will be `1.725eV`C. The longest wavelength which will eject the photo electrons from the surface is nearly `610nm`D. The maximum `K.E`. Will increase if the intesity of radiation is increased
• In photoelectric effect, which of the following property of incident light will not affect the stopping potentialA. FrequencyB. WavelengthC. EnergyD. Intensity