Use Coupon: CART20 and get 20% off on all online Study Material

Total Price: R

There are no items in this cart.
Continue Shopping
Get instant 20% OFF on Online Material.
coupon code: MOB20 | View Course list

Get extra R 280 off


in d photoelectric effect are d electrons detected by an ammeter??

 wht will happen if we pass light of various frequencies???

nd wht is d reaction that leads to the ejection of electrons when d light strikes d surface of  d metal????(acc. to 11th std.)


6 years ago


Answers : (1)


Dear samidha,

The photoelectric effect refers to the emission, or ejection, of electrons from the surface of, generally, a metal in response to incident light.

Energy contained within the incident light is absorbed by electrons within the metal, giving the electrons sufficient energy to be 'knocked' out of, that is, emitted from, the surface of the metal.

Using the classical Maxwell wave theory of light, the more intense the incident light the greater the energy with which the electrons should be ejected from the metal. That is, the average energy carried by an ejected (photoelectric) electron should increase with the intensity of the incident light.

In fact, Lénard found that this was not so. Rather, he found the energies of the emitted electrons to be independent of the intensity of the incident radiation.

Einstein (1905) successfully resolved this paradox by proposing that the incident light consisted of individual quanta, called photons, that interacted with the electrons in the metal like discrete particles, rather than as continuous waves. For a given frequency, or 'color,' of the incident radiation, each photon carried the energy E = hf, where h is Planck's constant and f is the frequency. Increasing the intensity of the light corresponded, in Einstein's model, to increasing the number of incident photons per unit time (flux), while the energy of each photon remained the same (as long as the frequency of the radiation was held constant).

Clearly, in Einstein's model, increasing the intensity of the incident radiation would cause greater numbers of electrons to be ejected, but each electron would carry the same average energy because each incident photon carried the same energy. [This assumes that the dominant process consists of individual photons being absorbed by and resulting in the ejection of a single electron.] Likewise, in Einstein's model, increasing the frequency f, rather than the intensity, of the incident radiation would increase the average energy of the emitted electrons.

Both of these predictions were confirmed experimentally. Moreover, the rate of increase of the energy of the ejected electrons with increasing frequency, which can be measured, enables one to determine the value of Planck's constant h.

The photoelectric effect is perhaps the most direct and convincing evidence of the existence of photons and the 'corpuscular' nature of light and electromagnetic radiation. That is, it provides undeniable evidence of the quantization of the electromagnetic field and the limitations of the classical field equations of Maxwell.


We are all IITians and here to help you in your IIT JEE preparation.

All the best.

If you like this answer please approve it....

win exciting gifts by answering the questions on Discussion Forum

Sagar Singh

B.Tech IIT Delhi

6 years ago

Post Your Answer

Other Related Questions on Inorganic Chemistry

The set representing the correct order of first ionisation potential is- K Be>Mg>Ca B>C>N Ge>Si>C
In the period the ionisation potential increases and in the group it decreases. thus, Be Mg and Ca are in group therefore othe order is correct.
Vikas TU 2 months ago
Explain why a sigma bond is stronger than a pi bond.
sigma bond is formed due to head on head overlapping of s orbitals. so ,they form stronger bonds as compared to pi bond which is formed due to parallel overlapping and gets easily broken...
ankit saurav 13 days ago
While drawing a structure of a compound how do we decide that where to place the Lone pair
@ rahul u can place that anywhere , no doub t for symmatry , just u need to be clear with the meaning of the loan pair , that means theses are the electron pairs which cannot participate in ...
Umakant biswal 12 days ago
The l.p. should arrange in this way thatl.p.----l.p. don`t allow on 90° and l.p-----b.p.(bond pair) is≥ 120° .And keep in mind less repultion between l.p.and b.p.
satish gupta 6 days ago
Does Paula Bruice Yurkanis Organic chemistry book contains extra stuff which is not necessary for JEE?
Yes, actually, this book is for analytical organic chemistry, which is also used for industrial chemical engg branch. I would like to suggest you to go for either Solomen or Morrison and...
Saurabh Kumar 3 months ago
@ siddhi Yes , they are actually higher than the level of JEE advanced exam . for jee u can refer to the 1- ncert 2- o.p tandon / morrision boyd . (any one ) 3- reaction mechanism in...
Umakant biswal 3 months ago
why p mitrophenol is major product than o nitrophenol ?
@ yogesh in the case of para nitrophenol , the interaction between the molecules are stronger due to intermolecular hydrogen bonding . and results in more stability and majority also . on...
Umakant biswal one month ago
How errors are identified in analytical chemistry?how chromatography is performed?
Dear student I did’t enderstand by the term errrs over here.Can you be a little more specific.Moreover you can follow the following link for studying analytical chemistry...
Bhavya one month ago
@ trapti chromatography is a physical method of separation that distribute the components between two phases one is stationary and the other is mobile phase or non stationary phase . it is...
Umakant biswal one month ago
View all Questions »

  • Complete JEE Main/Advanced Course and Test Series
  • OFFERED PRICE: R 15,000
  • View Details
Get extra R 3,000 off

Get extra R 280 off

More Questions On Inorganic Chemistry

Ask Experts

Have any Question? Ask Experts

Post Question

Answer ‘n’ Earn
Attractive Gift
To Win!!!
Click Here for details