Using conservation laws show that an electron cannot absorb a photon completely.
[ Hint : `hv = mc^(2) - m_(0)c^(2)` and `(hv)/(c) = mv`]

Statement-1:An isolated and free electron cannot absorb a photon completely. Statement-2 : All material particles behave wave like when in motion. Statement-3: Light of intensity l , falls normally upon a plane mirror (perfectly reflecting surface ). The pressure exerted is "2l"/c

Calculate the threshold freqency of the metalfrom the photoelectronsare emitted with zero velocity when exposed to radiation of wavelength 6800 Å Hint : KE = (1)/(2) mv^(2) hv= hv_(0) + KE, KE=0 v= (c ) /( lambda)

(i) In the explanations of photoelectric effect, we assume one photon of frequency v collides with an electron and transfer its energy. This leads to the equation for the maximum energy E_(max) of the emitted electron as E_(max)=hv-phi_(0) Where phi_(0) is the work function of the metal. if an electron absorbs 2 photons (each of frequency v) what will be the maximum energy for the emitted electron? (ii) Why is this fact (two photon absorption) not taken into consideration in our discussion of the stopping potential?

Statement-1: In Photoelectric effect , electrons absorbing the photon can not be a free electron. Statement -2: A free electron can't absorb a photon completely

In problems involving electromagenetism it is often convenlent and informative to express answers in terms of a constant, alpha , which is a combination of the Coulomb constant, k_(e) = 1//4piepsi_(0) , the charge of the electron, e, and h = h//2 , h being Planck's constant. For instant, the lowest energy that a hydrogen atom can have is given by E = 1//2 alpha^(2) mc^(2) , wherer m is the mass of the electron and c is the speed of light. Which of the following is the correct expression for alpha ? (HINt : non-relativistic kinetic energy is 1//2 mv^(2) , where v is speed.)

In the photoelectric effect the eletrons are emiited intantaneously from a given matal plate when it is irradiated with radiation of frequency equal to or greater then some minimum ferquency, is called the threshold frequency.According to Planck's idea, light may be considered to be made up discrete particles called photons.Each photon carries energy equal ti hv.When this photon cllides with the electron of the metal, the electron acquires energy of the emitted electron is given by : hv=K.E_("maximum")+PE=(1)/(2)m u^(2)+PE If the incident rediation is of threshold frequency the electron will be emitted without any kinetic energy i.e hv_(0) :.(1)/(2)m u^(2)=hv-hv_(0) A plot of kinetic energy of the emitted electron versus frequency of the incident radiation yields a straight line given as : A beam of white light is dispersed into its wavelenght components of potassium metal. What of the electron emitted by the different light component ?

In the photoelectric effect the eletrons are emiited intantaneously from a given matal plate when it is irradiated with radiation of frequency equal to or greater then some minimum ferquency, is called the threshold frequency.According to Planck's idea, light may be considered to be made up discrete particles called photons.Each photon carries energy equal ti hv.When this photon cllides with the electron of the metal, the electron acquires energy of the emitted electron is given by : hv=K.E_("maximum")+PE=(1)/(2)m u^(2)+PE If the incident rediation is of threshold frequency the electron will be emitted without any kinetic energy i.e hv_(0) :.(1)/(2)m u^(2)=hv-hv_(0) A plot of kinetic energy of the emitted electron versus frequency of the incident radiation yields a straight line given as : The number of photoelectrons emitted depends upon :

In the photoelectric effect the eletrons are emiited intantaneously from a given matal plate when it is irradiated with radiation of frequency equal to or greater then some minimum ferquency, is called the threshold frequency.According to Planck's idea, light may be considered to be made up discrete particles called photons.Each photon carries energy equal ti hv.When this photon cllides with the electron of the metal, the electron acquires energy of the emitted electron is given by : hv=K.E_("maximum")+PE=(1)/(2)m u^(2)+PE If the incident rediation is of threshold frequency the electron will be emitted without any kinetic energy i.e hv_(0) :.(1)/(2)m u^(2)=hv-hv_(0) A plot of kinetic energy of the emitted electron versus frequency of the incident radiation yields a straight line given as : A laser producting monochromatic lights of different wavelenght is uesd to eject electrons from the sheet of glod having threshold frequency 6.15xx10^(14)s^(-1) Which of the following incident rediation will be suitable for the ejecting of electrons ?

A meter stick of length l and mass M lies on a frictionlesss table. The stick is free to move in any way on the table. A hockey ball of mass m moving perpendicuarly to the mass of the ball so that it remains at rest immediately after the collision? [Hint: Elastic collision means that kinetic energy is conserved in the process. Consider conservation of kinetic energy, conservation of angualr momentum and linear momentum, i.e., 1/2mv^(2) = (1/2Mv^(2') + 1/2Iepsilon^(2) , mv1/2 = Iepsilon , mv = Mv^(') . Eliminate v^(2') and w^(2) from the first with the help of the other two. Use the expression I = 1/12 MI^(2)]