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• CBSE×
• Class 12 Science×
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• Dual Nature Of Radiation And Matter×
• Photoelectric Effect×

# Photoelectric Effect Free Doubts and Solutions

## numericals based on einstein photoelectric equation

Asked by khushimassey437 31st May 2019, 8:41 AM

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## Calculate no of photons passing through a ring of unit area in unit time if light of intensity 100 wm -2 and wavelength  400nm is fallingnormally on the ring

Asked by manasvijha 19th March 2019, 7:17 PM

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## what are the laws of photo electric effect ?

Asked by pksunilnair 4th December 2017, 9:27 AM

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## .

Asked by yugibo 13th April 2016, 10:54 PM

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## Monochromatic light with a frequency well above the cutoff frequency is incident on the emitter in a photoelectric effect apparatus. The frequency of the light is then doubled while the intensity is kept constant. How does this affect the photoelectric current? (A) The photoelectric current will increase. (B) The photoelectric current will decrease. (C) The photoelectric current will remain the same. (D) None of these         explain also

Asked by yugibo 13th April 2016, 8:54 PM

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## In a photoelectric experiment, the collector plate is at 2.0V with respect to the emitter plate made ofcopper = 4.5eV). The emitter is illuminated by a source of monochromatic light of wavelength 200nm. (A) the minimum kinetic energy of the photoelectrons reaching the collector is 0. (B) the maximum kinetic energy of the photoelectrons reaching the collector is 3.7eV. (C) if the polarity of the battery is reversed then answer to part A will be 0. (D) if the polarity of the battery is reversed then answer to part B will be 1.7eV.

Asked by yugibo 13th April 2016, 8:52 PM

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## Photons with energy 5 eV are incident on a cathode C , on a photoelectric cell. The maximum energy of the emitted photoelectrons is 2 eV. When photons of energy 6 eV are incident on C, no photoelectrons will reach the anode A if the stopping potential of A relative to C is (A) 3 V (B) – 3V (C) – 1V (D) 4 V

Asked by yugibo 13th April 2016, 8:48 PM

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## W of 5000 Å light is directed on a photoelectric cell. If the current in the cell is 0.16 A, the percentage of incident photons which produce photoelectrons, is (A) 0.4% (B) 0.04% (C) 20% (D) 10%      I am having too much doubt in these type of questions. so please explain clearly and in detail. and explain step by step.

Asked by yugibo 13th April 2016, 8:42 PM

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## The half life of Co-60 is 5.27 years. If the activity of a Co-60 source is 5000 Ci./ find (1) the number of radio active nuclei in the source (2) the activity of the source after 1 year.

Asked by rutujasarangmehta 15th March 2016, 7:28 PM

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## The half life of radio active radon is 3.8 days. find the activity of 10g of radon, given , atomic weight of radon = 222 and Avagadro's number = 6.025 x 10 raise to 23

Asked by rutujasarangmehta 15th March 2016, 7:24 PM

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## The half life of radium is 1600 years . In how many years will !g of radium loses 1 centigram weight of radon = 222 and Avogadro"s number = 6.025 x 10 raise to 23

Asked by rutujasarangmehta 15th March 2016, 7:21 PM

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## Calculate the binding energy and binding energy per nucleon of 26Fe raise to 56 nucleus. given, Mass of proton = 1.007825amu Mass of neutron = 1.008665amu Mass of Fe = 55.934932 amu

Asked by rutujasarangmehta 15th March 2016, 7:17 PM

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## find the binding energy and binding energy per nucleon of 3Li raise to 7 nucleus . Given, mass of proton + 1.00782amu Mass of neutron = 1.00866amu Mass of Li raise to 7=7.01599amu

Asked by rutujasarangmehta 15th March 2016, 7:13 PM

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## The ground state energy of hydrogen is -13.6 eV.  (1) What are the potential and kinetic energies of an electron in the 3rd exited state? (2) if the electron jumps to the ground state from the 3rd exited state , calculate the frequency of the photon emitted.

Asked by rutujasarangmehta 15th March 2016, 7:06 PM

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## The wavelength of the first member of Balmer series in the hydrogen spectrum is 6563 A. Calculate the wavelength of the first member of lyman series in the same spectrum.

Asked by rutujasarangmehta 15th March 2016, 7:00 PM

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## The first member of Balmer series of hydrogen spectrum has a wavelength 6563 A. compute the wavelength of second member.

Asked by rutujasarangmehta 15th March 2016, 6:56 PM

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## Radiation of wave length 180 nm ejects photo electrons from a plate whose work function is 2.0eV. If a uniform magnetic field of flux density 5.0 x 10raise to -5 T is applied to the plate, what should be the radius of the path followed by electrons ejected normally from the plate with maximum energy?

Asked by rutujasarangmehta 15th March 2016, 6:53 PM

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## The work function for an emitter is 4.2eV. How much potential difference will be required to stop photo emission of maximum energy electrons emitted by light of wavelength of incident light, the stopping potential would be zero?

Asked by rutujasarangmehta 15th March 2016, 6:44 PM

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## Photoelectric work function of metal is 1eV. Light of wavelength 3000 A falls on it. What is the velocity of the ejected photo electron?

Asked by rutujasarangmehta 15th March 2016, 6:39 PM

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## Light of wavelength 500nm falls on a metal whose work function is 1.9 eV . Find (1) the energy of the photon in eV (2) the kinetic energy of the photoelectron emitted and (3) the stopping potential. Given h=6.625x10raise to -34 Js.

Asked by rutujasarangmehta 15th March 2016, 6:36 PM

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## An electron and a Photon has same de-broglie wavelength.Which among them will have higher Kinetic energy and higher Total energy?explain.

Asked by Tanya raj 15th January 2016, 11:53 AM

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## Light of intensity ‘I’ and frequency ‘n’ is incident on a photosensitive surface and causes photoelectric emission. What will be the effect on anode current when(i) the intensity of light is gradually increased, (ii) the frequency of incident radiation is increased, and (iii) the anode potential is increased? In each case, all other factors remain the same. Explain, giving justification in each case.

Asked by Topperlearning User 8th July 2015, 1:43 PM

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## how that de Broglie hypothesis of matter waves is in agreement with Bohr's theory.

Asked by mahesh010167 3rd March 2015, 8:26 PM

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## 20. The data given below gives the photon energy (in eV) for a number of waves whose wavelength values (in nm) are also given.  Wavelength (in nm) 200 400 600 800 1000 1200 Photon Energy (in eV) 6.216 3.108 2.072 1.554 1.243 1.036 (Without doing any calculation/taking any reading), explain how one can use this data to draw an appropriate graph to infer (i) photon energy corresponding to a wavelength of 100 nm. (ii) the wavelength value (in nm) corresponding to a photon energy of 1 eV. (iii) velocity of light assuming that the value of Plank’s constant is known.

Asked by Malavika Umesh 25th February 2015, 9:36 AM

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## If photon is a particle then why do we associate wavelength and frequency with it?

Asked by Nishtha Sardana 23rd November 2014, 9:08 PM

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## if every metal has a definite work function then why don't photoelectrons eject with same kinetic energy if the incident radiation is monochromatic and has a fixed energy?

Asked by Sahib Sodhi 25th October 2014, 6:30 PM

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## Plot a graph showing the variation of stopping potential with the frequency of incident radiation for two different photosensitive materials having work functions w1 and w2 (w1 > w2). On what factors does the (i) slope and (ii) intercept of the lines depend?

Asked by Topperlearning User 4th June 2014, 1:23 PM

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## In a plot of photoelectric current versus anode potential, how does (i) the saturation current vary with anode potential for incident radiations of different frequencies but same intensity? (ii) the stopping potential vary for incident radiations of different intensities but same frequency? (iii) Photoelectric current vary for different intensities but same frequency of incident radiations? Justify your answer in each case.

Asked by Topperlearning User 4th June 2014, 1:23 PM

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## 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?

Asked by Topperlearning User 4th June 2014, 1:23 PM

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## Photon is a quanta of light. (a) Who introduced the concept of photon? (b) Briefly explain the effect of intensity and energy of the incident radiation on the photo electric effect.

Asked by Topperlearning User 4th June 2014, 1:23 PM

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## (a) Why photoelectric effect can not be explained on the basis of wave nature of light? Give reasons. (b) Write the basic features of photon picture of electromagnetic rediation on which Einstein's photoelectric equation is based.

Asked by Topperlearning User 4th June 2014, 1:23 PM

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## The given graph shows the variation of photo-electric current (I) versus applied voltage (V) for two different photosensitive materials and for two different intensities of the incident radiation. Identify the pairs of curves that correspond to different materials but same intensity of incident radiation.

Asked by Topperlearning User 4th June 2014, 1:23 PM

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## Plot a graph showing the variation of photoelectric current with anode potential for two light beams of same wavelength but different intensity.

Asked by Topperlearning User 4th June 2014, 1:23 PM

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## If the frequency of light falling on a metal is doubled, what will be the effect on photocurrent and the maximum kinetic energy of emitted photoelectrons? Explain.

Asked by Topperlearning User 4th June 2014, 1:23 PM

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## Define the following terms for a given photosensitive surface : i. Thershold frequency, and      ii. Work function.

Asked by Topperlearning User 4th June 2014, 1:23 PM

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## An increase in the frequency of the incident radiation increases the maximum kinetic energy of the photoelectron. Explain How?

Asked by Topperlearning User 4th June 2014, 1:23 PM

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## Why does photoelectric emission not take place if the frequency of incident radiation is less than threshold value?

Asked by Topperlearning User 4th June 2014, 1:23 PM

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## Why is it difficult to remove a free electron from copper than sodium? Which has higher threshold wavelength?

Asked by Topperlearning User 4th June 2014, 1:23 PM

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## Why are alkali metals most suited for photoelectric emission?

Asked by Topperlearning User 4th June 2014, 1:23 PM

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## Why does the maximum velocity photoelectron not depend upon the intensity of radiation?

Asked by Topperlearning User 4th June 2014, 1:23 PM

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## Explain intensity of radiation in terms of wave theory and photon theory

Asked by Topperlearning User 4th June 2014, 1:23 PM

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## How does photon theory explain photoelectric effect?

Asked by Topperlearning User 4th June 2014, 1:23 PM

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## Can photoelectric effect  be explained on the basis of wave theory of radiation?

Asked by Topperlearning User 4th June 2014, 1:23 PM

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## why it is not advice to not keep a metallic object like iron in the microvawe oven and what is the theory behind it?

Asked by Rahul Mishra 31st May 2014, 6:04 PM

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## Plot a graph showing the variation of stopping potential with the frequency of incident radiation for two different photosensitive materials having work functions W1 and W2 (W1>W2). On what factors does the (i) slope and (ii) intercept of the lines depend?

Asked by Topperlearning User 19th May 2014, 4:16 PM

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## Ultraviolet light is incident on two photosensitive materials having work functions W1 and W2 (W1 > W2). In which case will kinetic energy of the emitted electron be greater ? Why ?

Asked by Topperlearning User 19th May 2014, 4:04 PM

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## Define the term work function of a metal. The threshold frequency of a metal is f0. When the light of frequency 2f0 is incident on the metal plate, the maximum velocity of electron emitted is v1. When the frequency of the incident radiation is increased to 5f0, the maximum velocity of electrons emitted is v2. Find the ration of v1 to v2.

Asked by Topperlearning User 19th May 2014, 3:52 PM

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## Ultraviolet light of wavelength 2271 Å from a 100 W mercury source irradiates a photocell made of molybdenum metal. If the stopping potential is -1.3 V, estimate the work function of the metal. How would the photocell respond to a high intensity (~ 105 Wm-2) red light of wavelength 6328 Å produced by a He-Ne laser ? (Given: h = 6.63 x 10-34 Js, c = 3 x 108 m/s)

Asked by Topperlearning User 19th May 2014, 3:46 PM

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## The work function of cesium is 1.8 eV. Light of 5000 is incident on it. Calculate (i) Threshold wavelength (ii) Maximum K.E of emitted electrons (iii) Maximum velocity of emitted photoelectric electrons. Take h=6.63x10-34J; c=3X108m/s ; m=9X10-31Kg

Asked by Topperlearning User 19th May 2014, 3:33 PM

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## Monochromatic radiation of frequency greater than threshold value is incident on a metal. Why do all the photoelectrons not come with the same kinetic energy?

Asked by Topperlearning User 19th May 2014, 2:52 PM