CBSE 2023 Term II Ki Tayari Dobtnut Ke Sath#!#Parabola - Practice Session

Which of the following is correct regarding photo-electric effect? (i) The photo-electric effect takes place if lambda le lambda_(0) or upsilon ge upsilon_(0) . maximum K.E. of photo-electron K_(max) =hv=(hc)/(lambda) Einstein photo-electric effect equation hv=hv_(0) + K_(max) (ii) The maximum K.E. of electron or stopping potential V_(s)(K_(max) =eV_(s)) for a given metal depends only on frequency or wavelength of incident light and not on its intensity (iii) The saturation current (i =ne, n: number of photo-electrons ejected per unit time) depends on intensity and not frequency (iv) Normally it is assumed that one photon eject one electron. Practically several incident photons eject one electron. If quantum efficiency is given {"Quantum efficiency" =("Number of electrons ejected")/("Number of photons incident")} Number of electrons ejected must be calculated must be calculated and then calculate saturation current

The velocity of a particle moving in a straight line varies with time in such a manner that v versus t graph is represented by one-half of an ellipse. The maximum velocity is v_m and the total time of motion is t_0 (i) average velocity of the particle is (pi)/(4) v_m (ii) such motion cannot be realized in practical terms.

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Tha particle is executing SHM. The amplitude of motion is a. State those positions of the particle in terms of a when (i) the K.E. of the particle is zero (ii) P.E. is zero (iii) P.E. is one-fourth of the total energy (iv) P.E and K.E. are equal.