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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.

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)Sir,plz explain Davisson Germer experiment?

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

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 si the conclusion of Davisson and Germer experiment?

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

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

Plzz tell the answer pah...

Q.15. The work function for tungsten and sodium are 4.5 eV and 2.3 eV respectively. If the threshold wavelength for sodium is 5460 Å, the value of $\lambda $ for tungsten is

(1) 5893 Å

(2) 10683 Å

(3) 2791 Å

(4) 528 Å

explain the photovoltaic cells and photoconductive cells

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

define intensity of light?

Solve this :Q. Two small balls A and B, each of mass m, are joined rigidly at the ends of a light rod of length L. They are placed on a frictionless horizontal surface. Another ball of mass 2 m moving with speed u towards one of the ball and perpendicular to the length of the rod on the horizontal frictionless surface as shown in the figure. If the coefficient of restitution is 1/2 then the angular speed of the rod after the collision will be :

$\left(\mathrm{a}\right)\frac{4}{3}\frac{\mathrm{u}}{\mathrm{L}}\left(\mathrm{b}\right)\frac{\mathrm{u}}{\mathrm{L}}\phantom{\rule{0ex}{0ex}}\left(\mathrm{c}\right)\frac{2}{3}\frac{\mathrm{u}}{\mathrm{L}}\left(\mathrm{d}\right)\mathrm{None}\mathrm{of}\mathrm{these}$

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.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?

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 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..

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.

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

draw a graph showing the variation of de broglie wavelength of an electron with variation of its momentum

hertz and lenard's observations in photoelectric effect

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?

_{1}→ n_{2}where n_{1}and n_{2}are the principal quantum numbers of two states. Assume the Bohr model to be valid. The time period of the electron in the initial state is eight times that is in the final stage. The possible values of n_{1}& n_{2}are(A) n

_{1}= 4, n_{2}= 2 (B) â€‹n_{1}= 8, n_{2}= 2 (C) â€‹n_{1}= 8, n_{2}= 1 (D) â€‹n_{1}= 6, n_{2}= 3why does the bluish color predominate in a clear sky

11.Two isotopes P and Q of atomic weight 10 and 20, respectively are mixed in equal amount by weight. After 20 days their weight ratio is found to be 1 : 4. Isotope P has a half-life of 10 days. The half-life of isotope Q is(1) Zero (2) 5 days (3) 20 days (4) infinite

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

(b)= 927 deg cel

(c)= 327 deg cel

(d)= 54 deg cel

10^-3W of 5000 A light is directed on a photo electric cell.if the current in the cell is o.16 micro ampere,then find the percentage of incident photons which produce photoelectrons

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

DERIVE EINSTEINS PHOTOELECTRIC EQUATION?

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.

^{6}m/s. what frequency of radiation must be used?. Given threshold frequency of potassium is 4.2x10^{14}Hztwo metals A and b have work function 2eV and 4eV respectively which of the metals has a smaller threshold wavelenght? pls solve ftafat

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

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.

31. Light with an energy flux of 25 $\times $ 10

^{4}Wm^{-2}falls on a perfectly reflecting surface at normal incidence. If the surface area is 15 cm^{2}, the average force exerted on the surface is :-(1) 1.25 $\times $ 10

^{-6}N (2) 2.50 $\times $ 10^{-6}N(3) 1.20 $\times $ 10

^{-6}N (4) 3.0 $\times $ 10^{-6}NWhy de broglie waves associated with a moving football are not visible?

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

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.

Explain the laws of photoelectric effect with the help of Einstein's Photoelectric Equation?Q7. Find the retarding potential required to stop electron of the de Broglie wavelength 0.5 nm.

Hint : ${\mathrm{eV}}_{\mathrm{s}}=\frac{\mathrm{hc}}{\mathrm{\lambda}}$

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.?

Two metals A B have work functions 4 eV 10 eV respectively. Which metal has lower threshold frquency?

What is the

(a)momentum,(b)speed, and(c)de Broglie wavelength of an electron with kinetic energy of 120 eV.find the frequency of 1 Mev photon.given wavelength of a 1 Kev photon is 1.24*10^-9m

Can pair production take place in vaccum..?

what is velocity selector?

DERIVE EINSTEINS PHOTOELECTRIC EQUATION?

The radiation force experienced by body exposed to radiation of intensity I, assuming surface of body to be perfectly absorbing is :

a) $a)\frac{\pi {R}^{2}I}{c}b)\frac{\pi RHI}{c}c)\frac{IRH}{2c}d)\frac{IRH}{c}$

formula for stopping potential?

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})## A block of mass 10 kg is held at rest against a rough vertical wall (μ= 0.5 ) under the action a force F . The minimum value of F required for it is (g=10 ms-2)

pls explain properly162.6 N

89.7 N

42.7 N

95.2N

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

have same energy E. What is the ratio of their wavelenght?

3. Why GaAs is better than Si for making solar cells?

an electron,proton and an alpha particle have the same kinetic energy.which of these particles hae the shortest de-broglie wavelength?

A photon of wavelength 3310 A

^{o}falls on a photo cathode and an electron of energy 3 x 10^{-9}Jis ejected. If the wavelength of the incident photon is changed to 5000 A^{o},the energy of the ejected electron is 9.71 x 10-20 J.Calculate the value of Plank's constant and threshold frequency.