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Syllabus

An alpha particle and a proton are accelerated from rest through the same potential difference V. Find the ratio of de-Broglie wavelengths associated with them.

^{2}illuminates a perfectly absorbing cylinder of radius 5 cm and height 10 cm as shown in figure. The force that light exerts on the cylinder in micro newton is(A) 0.3 (B) 3.0 (C) 0.6 (D) 0.8

Sir,plz explain Davisson Germer experiment?

1. explain how Einstein's photoelectric equation enables us to understand the :- a) linear dependence,of the maximum kinetic energy of the emitted electrons,on the frequency of the incident radiation. b) existence of a threshold frequency for a given photoemitter.

write the laws of photoelectric effect by using Einstein's photo electric equations.

light at a place is given as E = Eo sin (wt) which falls on a metal surface having work function W. calculate the max. K.E. of a photoelectron.

What si the conclusion of Davisson and Germer experiment?

a) 100 %

b) 50%

c) 41%

d) 73%

Define intensity of radiation on the basis of photon picture of light. Write its SI unit.

Plzz tell the answer pah...

of light incident on the surface changes from lambda1 to lambda2. Derive the expressions for the

threshold wavelength lambda

_{o}and work function for the metal surface.The following graph shows the variation of stopping potential

V_{0}with the frequency ν of the incident radiation for two photosensitive metals X and Y:(i) Which of the metals has larger threshold wavelength? Give reason.

(ii) Explain giving reason, which metal gives out electrons, having larger kinetic energy, for the same wavelength of the incident radiation.

(iii) If the distance between the light source and metal X is halved, how will the kinetic energy of electrons emitted from it change? Give reason

(i) Let = Frequency of incident radiations of metal Y

= Frequency of incident radiations of metal X

Therefore, metal X has larger threshold wavelength.

(ii) Since the kinetic energy of the emitted electrons is directly proportional to the frequency of incident radiation, metal Y having larger incident frequency will have larger kinetic energy.

∴ Metal Y has larger kinetic energy.

(iii) Kinetic energy of the emitted photoelectrons is independent of the intensity of the incident light. Hence, kinetic energy of the emitted photoelectrons remains unchanged if the distance between the light source and metal X is halved.

in this in (ii) part why work function.is not considered kindly reply fast... ??When a given photosensitive material is irradiated with light of frequency V , the maximum speed of the emitted photoelectrons equals Vmax. The square of Vmax, i.e., Vmax2, is observed to vary with , as per the graph shown here. Obtain expressions

(i) Planck’s constant, and

(ii) The work function of the given

photosensitive material,

in terms of the parameters n and the mass, m, of the electron.

The wavelength lambda , of a photon & the de-broglie wavelength of an electron have the same value.show that the energy of the photon is (2*lambda*m*c)/h times the kinetic energy of the electron, where m,c,h have their usual meanings..

^{-13}kgm /s. Given Planck's constant to be 6.6 x 10^{-34 }Js(a) 7.3 x 10

^{4}J (b) 9.9 x 10^{-5}J(c) 1.3 x 10

^{5}J (c) 8.1 x 10^{3}jexplain the photovoltaic cells and photoconductive cells

The work function of caesium is 2.14eV.find a)threshold frequency.b) the wavelength of incident light if the photocurrent is brought to zero by a stopping potential of 0.60v

What is the shortest wavelength present in the Paschen series of spectral lines?

Given that photon of light of wavelength 10000 A

^{o}has an energy equal to 1.23 eV. When a light of wavelength 5000A^{o}adn intnsity I falls on photoelectric cell, the surface current is 0.40 X 10^{6}A. Stopping potential is 1.36eV, then what is the work function? (1 A^{o }=^{ }10^{-10}m)define intensity of light?

how p=hv/c? plz explain

If the frequency of incident light on a metal surface is doubled for the same intensity . What is the change observed in Kinetic Energy of the photoelectrons emitted?

Define the terms threshold frequency and stopping potential in relation to the phenomenon of photoelectric effect. How is the photoelectric current affected on increasing the (i) frequency (ii) intensity of the incident radiations and why?

An electron and a photon each have a wavelength of 1.00 nm. Find

(a)their momenta,(b)the energy of the photon, and(c)the kinetic energy of electron.draw a graph showing the variation of de broglie wavelength of an electron with variation of its momentum

AN ELECTRON AND ALPHA PARTICLE HAVE THE SAME de-Broglie WAVE LENGTH ASSOCIATED WITH THEM .HOW ARE THEIR KINETIC ENERGIES RELATED ?

hertz and lenard's observations in photoelectric effect

b) Explain the laws of photoelectric emission on the basis of Einstein's photoelectric equation.

if the same source is placed 0.6 m away from the photoelectric cell then find the new stopping potential and saturation current.

why does the bluish color predominate in a clear sky

(b)= 927 deg cel

(c)= 327 deg cel

(d)= 54 deg cel

why are matter waves not electromagnetic in nature ? explain

An unpolarised light is incident on the boundary between two transport media.State the condition when the reflected wave is totally plane polarised. Find out the expression for the angle of incidence in this case.

Q70. At an instant, two electrons are moving with same speed v : one in region of uniform electric field and other in uniform magnetic field. After some time if de Broglie wavelength of two electrons respectively are ${\lambda}_{1}$ and ${\lambda}_{2}$ then

(a) ${\lambda}_{1}$ = ${\lambda}_{2}$ (b) ${\lambda}_{1}$ > ${\lambda}_{2}$

(c) ${\lambda}_{1}$ < ${\lambda}_{2}$ (d) Both (b) & (c) possible

The stopping potential in an experiment on photo electric effect is 1.5V. What is the max K.E of the photo electrons emitted ?

Why wave nature of light fails to satisfy photoelectric effect....?

DERIVE EINSTEINS PHOTOELECTRIC EQUATION?

Light of frequency 1.5 times the threshold frequency is incident on a photo-sensitive material. if the frequency is halved and intensity is doubled,the photo current becomes?

infra red radiations cannot produce photocurrent.

explain if these two statements are true or false with explainantion?

two metals A and b have work function 2eV and 4eV respectively which of the metals has a smaller threshold wavelenght? pls solve ftafat

Define threshold frequency?How does the maximum kinetic energy of electrons emitted vary with the work function of the metal??

Q 183.Rock salt forms a cubic lattice with sides of each cube having a length of 5.63 $\stackrel{\xb0}{A}$. The least potential difference across which the electrons should be accelerated so that they are reflected strongly by dashed planes indicated by dashed lines is(1) 2.44 V (2) 5.44 V (3) 7.44 V (4) 9.18 V

An alpha particle after passing through a potential difference of 2 M V falls on a silver foil. The atomic number of silver is 47. Calculate (1) K.E. of alpha particle at a distance of 50 fm from the nucleus and (2) the shortest distance from the nucleus of silver to which the alpha particle reaches.

sir in formula kmax = eVo why it is not only Kmax = Vo for maximum energy of electron

De-broglie wavelength associated with an electron accelerated through a potential difference V is lambda. , what will b its wavelength , when accelerating potential is increased to 4V.

Here, why cant we use the formula '' lambda= 1.22/root V '' and this formula is applicable in what type of quests.?

_{0}_{,}ν_{0’}) respectively.(Given : ν_{0 }is lesser than ν_{0’}_{)}(i) Which one of the two metals A or B has higher work function?

(ii) What information do you get from slope of the graph?

(iii) What does the value of the intercept of graph A on the potential axis represents? (3

Explain giving reason in which case more number of electrons will be emitted.

Q.11. A metal surface of work function 1.07 eV is irradiated with light of wavelength 332 nm. The retarding potential required to stop the escape of photo electron is

(1) 4.81 V

(2) 3.74 V

(3) 2.65 V

(4) 1.07 V

7. Which of the following statements concerning photoelectric effect is false?

(1) It displays the particle nature of light .

(2) Electrons are emitted only if light has a frequency equal to or above that of a critical frequency .

(3) All electrons emitted at a particular frequency of light have the same energy .

(4) Changing the frequency of light changes the energies of the electrons.

Why de broglie waves associated with a moving football are not visible?

Q.1. The work function of a metal is 4 eV if 5000 Å wavelength of light is incident on the metal. Is there any photo electric effect?

_{0}. When the same surface is illuminated by light of wavelength 1.5 λ then the stopping potential becomes V_{0}. Find the value of threshold wavelength for photoelectric emission.Explain the laws of photoelectric effect with the help of Einstein's Photoelectric Equation?Determine the de-Broglie wavelength of a proton whose kinetic is equal to rest mass energy of an electron (rest mass energy = m_{0}c^{2 }& m_{p}= 1840m_{e})why is quartz window used in experiment for photoelectric effect?

DERIVE EINSTEINS PHOTOELECTRIC EQUATION?

2 positive charges 9nc and 4nc are placed at the points A and C respectively of a right angled triangle ABC in which angle B =90,AB=3cm and BC=2cm.find the magnitude and direction of the resultant electric field at B.

What is the

(a)momentum,(b)speed, and(c)de Broglie wavelength of an electron with kinetic energy of 120 eV.What will be the day de Broglie wavelength of the neutron corresponding to root mean square speed at 27?C?

Please answer with detailed solutions

i think kmax=( h*frequency) - work function

what is velocity selector?

Can you explain the Davission and Germer Experiment(interferance) in more simpler way?

Can pair production take place in vaccum..?

Q57. The surface of metal with work function $\mathrm{\varphi}$ is illuminated by electromagnetic radiation whose electric field component is E = a (1 + cos$\mathrm{\omega}$t) cos$\mathrm{\omega}$t. Then maximum kinetic energy of photoelectron liberated from surface is (here $\mathrm{\omega}$ > $\mathrm{\omega}$

_{0})(a) $\frac{h}{2\mathrm{\pi}}$$\mathrm{\omega}$ – $\mathrm{\varphi}$ (b) $\frac{{\mathrm{h\omega}}_{0}}{2\mathrm{\pi}}-\mathrm{\varphi}$

(c) $\frac{\mathrm{h}\left(\mathrm{\omega}+{\mathrm{\omega}}_{0}\right)}{2\mathrm{\pi}}-\mathrm{\varphi}$ (d) $\frac{\mathrm{h}\left(\mathrm{\omega}-{\mathrm{\omega}}_{0}\right)}{2\mathrm{\pi}}-\mathrm{\varphi}$

the extent of localisation of a particle is determined roughly by its de broglie wavelength.if an electron is localized within the nucleus (of size of about 10^-14m) of an atom, what is its energy?In the solution of this question wavelength is taken to be10^-14m. but i can't understand how size of nucleus is equal to wavelength?