# 2.1 Electromagnetic radiation & Line emission spectra  (Page 7/27)

 Page 7 / 27
$E=nh\nu ,\phantom{\rule{0.2em}{0ex}}n=1,\phantom{\rule{0.2em}{0ex}}2,\phantom{\rule{0.2em}{0ex}}3,\phantom{\rule{0.2em}{0ex}}. . .$

The quantity h is a constant now known as Planck's constant, in his honor. Although Planck was pleased he had resolved the blackbody radiation paradox, he was disturbed that to do so, he needed to assume the vibrating atoms required quantized energies, which he was unable to explain. The value of Planck's constant is very small, 6.626 $×$ 10 −34 joule seconds (J s), which helps explain why energy quantization had not been observed previously in macroscopic phenomena.

## The photoelectric effect

The next paradox in the classical theory to be resolved concerned the photoelectric effect ( [link] ). It had been observed that electrons could be ejected from the clean surface of a metal when light having a frequency greater than some threshold frequency was shone on it. Surprisingly, the kinetic energy of the ejected electrons did not depend on the brightness of the light, but increased with increasing frequency of the light. Since the electrons in the metal had a certain amount of binding energy keeping them there, the incident light needed to have more energy to free the electrons. According to classical wave theory, a wave's energy depends on its intensity (which depends on its amplitude), not its frequency. One part of these observations was that the number of electrons ejected within in a given time period was seen to increase as the brightness increased. In 1905, Albert Einstein was able to resolve the paradox by incorporating Planck's quantization findings into the discredited particle view of light (Einstein actually won his Nobel prize for this work, and not for his theories of relativity for which he is most famous).

Einstein argued that the quantized energies that Planck had postulated in his treatment of blackbody radiation could be applied to the light in the photoelectric effect so that the light striking the metal surface should not be viewed as a wave, but instead as a stream of particles (later called photons ) whose energy depended on their frequency, according to Planck's formula, E = (or, in terms of wavelength using c = νλ , $E=\phantom{\rule{0.2em}{0ex}}\frac{hc}{\lambda }$ ). Electrons were ejected when hit by photons having sufficient energy (a frequency greater than the threshold). The greater the frequency, the greater the kinetic energy imparted to the escaping electrons by the collisions. Einstein also argued that the light intensity did not depend on the amplitude of the incoming wave, but instead corresponded to the number of photons striking the surface within a given time period. This explains why the number of ejected electrons increased with increasing brightness, since the greater the number of incoming photons, the greater the likelihood that they would collide with some of the electrons.

With Einstein's findings, the nature of light took on a new air of mystery. Although many light phenomena could be explained either in terms of waves or particles, certain phenomena, such as the interference patterns obtained when light passed through a double slit, were completely contrary to a particle view of light, while other phenomena, such as the photoelectric effect, were completely contrary to a wave view of light. Somehow, at a deep fundamental level still not fully understood, light is both wavelike and particle-like. This is known as wave-particle duality    .

#### Questions & Answers

can I get Bengali meaning of these sentence?
Srabony Reply
How can I grow my knowledge about Economics to compete with world
Srabony Reply
you can start by change ur mind focus on economics issues you can grow by learning as well
TUYA
Can a PC help me for that?
Srabony
yes
Shubham
you can start with learning new words and their meanings. For Example - *the poverty trap*
Amitesh
#amitesh Are these words economics base?
Srabony
Yes you can use a PC but you have to be specific on what you want,read different books is another way!
TUYA
ok, tnQ
Srabony
#srabony yes it is, it is a economic condition where even after earning a person is not available to rise above poverty line.
Amitesh
Helow How is the poverty trap work on economics base? and how it affects individual earning!!
TUYA
definition of economics
Mustqeem Reply
hi guys can someone tell me all the economic policies
Tanaka
monetary and fiscal policy
Zz
we have 5 but the keys one are monetary, fiscal and physical
Souley
okay thank you
Tanaka
anyone with an idea of what type of inflation Zimbabwe is facing currently. Where a good used to be $1 now costing$3
Tanaka
It is hyper inflation
DADA
okay can I have an explanation of that type of inflation
Tanaka
hyper inflation is the inflation where price rises so fast causing damage to the country
Peter
You mean like the damage that my girlfriend caused to my heart?
Neil
oh..Neil what u askinh
shaikh
No I'm just joking
Neil
Lolz
Neil
How have you been Shaikhji
Neil
hi
Yusifu
Peter Ibeto you are right about hyper inflation. Hyper inflation is also a type of inflation in which general price level increase between 20-100%
The
hyper inflation totally destroys the monetary system of the country
The
Neil sorry
The
k..Neil..I'm good
shaikh
Lmao Joker in playin
Neil
*Im
Neil
hi
JUDE
hello guys
Sele
the country economy
Peter
hyper inflation is a kind of inflation that is uncontrollable.
DADA
so therefore, if the price level increases between 20-100'/. it means inflation can not be controlled.
DADA
hello dear,I am a green horn here..may I know more about you
Pello
may I ask a question too
Pello
go ahead with your question.
DADA
what is price determination
Folorunso Reply
This is the interaction between the forces of demand and supply, in order to establish the general price of goods and services.
Ejikeme
where is it?
Elbee
it is price determination
DADA
oh okay, got it
Elbee
what is the difference between monopoly and monopolistic
Tariro Reply
The difference is that monopoly is only one seller's or producer's market, while monopolistic has the characteristics of pure monopoly and perfect market.
DADA
You're right. but it is imperfect market not perfect market
The
I disagree
DADA
it is perfect market
DADA
oh. it's true it perfect market
The
yes
Ejikeme
Thanks for being very contributive.
DADA
I'm not
The
monopoly involve single seller with product with no close substitute while monopolistic involve many seller selling differentiated product with close substitute by not perfect substitute.
evelyn
*but
evelyn
Monopoly refers to a single seller dominating the whole market by selling his/her unique product. While, Monopolistic refers to the competitive market, where their are few sellers in the market offering near substitutes to the customers
Muhammad
monopoĺistic have large number of seller not few seller
evelyn
they have both large numbers of sellers and buyers
sheron
Ok, thanks for the correction
Muhammad
you welcome
sheron
monopoly -where a single seller ,sells products with no close substitute to a large number of buyers while monopolistic competition -where many sellers offers differentiated products to large number of buyers .
Ejikeme
guys please I'm in need of something like this but in logic and critical thinking any idea please...
Young
what do you need exactly ....features of a monopolistic market?...or just a defination?
sheron
here is based on economics but I need logic and critical thinking as this
Young
monopolistic does not have low number of sellers
The
sorry. monopolistic doesn't have large number of sellers. it had few sellers and a large amount of buyers
The
it's in a competitive market that you will find a larger number of sellers
The
yes thus why monopolistic market structure have some features of perfect competitive market and some features of monopoly
evelyn
few seller are in oligopoly not in monopolistic
evelyn
perfect market is a market where there are many seller and buyers who cannot influence the prices of goods and services because they are many.
Asatu
what is the diference durable consumer and non durable consumer
Xasan
hello
Xasan
Ibrahim...is it durable consumer or durable product?
shaikh
durable goods are those goods which do not wear out quickly and last for a long time. eg cars..appliances non durable goods are those goods that have a short life span..eg food products
sheron
what is the main of learning economics
Xasan
durable goods are assumed to never wear out (i.e. bricks) non-durable goods are also known as consumables (i.e. fuel and food)
William
means u wan ask y v study economics
shaikh
Probably
Neil
We study economics to better understand how we can allocate scarce resources to unlimited demand.
Neil
Furthermore, the concepts of Economics can be applied anywhere, from day to day life to happiness. So the importance of Econ is infinite
Neil
What is the PPc
vicky
the ppc curve is a curve that shows various combination if goods that an economy can produce with it available resources and technology at a period of time
Josu
what is term of trade?
Josu
what is income
Aisha
i mean Nstional income accounting?
Aisha
yes
francis
when does dimishing return set 0
Citizen
National income accounting is the measurement of all goods and services produced in a country
The
diminishing return start to operate when marginal product is at the maximum
evelyn
diminishing marginal returns/product sets at zero when total product is at its maximum
Romeo
okay
Citizen
g
Zz
hi my name is Ibeto Chukwudum I love economics but am studying agricultural back then when am in ss1
Peter
please between monopoly and monopolistic which one is the best
Peter
monopolistic competition is the best
DADA
you will also do agricultural economics
DADA
monopolistic compétition is the best
Josu
no
Josu
how please explain
Peter
because it sometimes comprises of large numbers of sellers/producers, free entry and exit, etc and these conditions make the sellers/producers to be a price taker(market price) not a price maker(influencing/controlling price). so upon this background, I conclude that it is the best.
DADA
thanks
Peter
law of demand's limitations and assumptions
Maheen Reply
what?
ehtesham
The limitation is the graphical representation of the law of demand which shows only two variables which is price and quantity demanded. it doesn't show other factors that influence quantity demanded such as income and price of other commodities
The
sorry I sent it thrice. it's because of bad connection
The
limitation of law of demand is exceptional demand where there is direct relationship between price and quantity demanded instead of inverse relationship btn price and quantity demanded. assumptions include no change in technology, no change in income, constant distribution of income.
evelyn
Oh. Evelyn that's true. Maheen my answer is wrong
The
Oh. Evelyn that's true. Maheen my answer is wrong
The
limitations it is not apply on snobbish people or very expressive good like diamond and also not apply on very cheap good like slat
Zz
assumption fashion taste weather papulation should not be changed otherwise law will be wrong
Zz
what is consumer equilibrium in two case commodity illustrate with diagram.....plz reply asap plz it's urgent
saumya Reply
a consumer will be in equilibrium when he spent his income on different good in such way that marginal utilities of each product will become equal
Zz
I guess investments in mutual funds could be its example?
Ahmad
any one who can tell me the best topic thesis in the field of economic. use 2 macro-economic variables.
Husein
national income as context to gst and demonitization and the inflation in current scenario lik raises petrol price and ruppee b cheap ..might b good for thesis
shaikh
when give the production of bread and pizza. where by bread produces 10 units and pizza 5 units. how do you calculate for the opportunity cost for bread and pizza
Jennifer Reply
6. The countries of Figistan and Blah are small island countries in the South Pacific. Both produce fruit and timber. Each island has a labor force of 1,200. The following table gives production per month for each worker in each country. a. Which country has an absolute advantage in the product
Bablu Reply
6. The countries of Figistan and Blah are small island countries in the South Pacific. Both produce fruit and timber. Each island has a labor force of 1,200. The following table gives production per month for each worker in each country. a. Which country has an absolute advantage in the producti
Bablu
We need to know the values to help
Neil
BASKETS OF FRUIT BOARD FEET OF TIMBER Figistan workers 10 5 Blah workers 30 10 Productivity of one worker for one month
Bablu
basket of fruit |basket of timber Figistan workers 10 5 Blah workers 30 10
Bablu
a. Which country has an absolute advantage in the production of fruit? Which country has an absolute advantage in the production of timber? b. Which country has a comparative advantage in the produc- tion of fruit? of timber? c. Sketch the ppf’s for both countries. d. Assuming no trading betwe
Bablu
where the table
Souley
my own idea is that we should divide the number of baskets of fruits and timber by labour force
The
Is it true. can somebody correct me
The
No not true
Neil
Absolute Advantage is determined by the numbers
Neil
You can't just divide it or something
Neil
For example, US makes 8 Cars and 6 Fish Canada makes 2 cars 3 fish US has absolute advantage in this scenario
Neil
Rawat thank you
The
Neil Rawat but a country is said to have absolute advantage over another country when it spends less time producing a commodity
The
For example, 8 cars are produced in one hour. how can we calculate the amount of time for producing one car
The
There are two types of Questions
Neil
Input and Output. The one that you just put and Bablu asked "Produced in one hour" or "in one month" is Input. Time is a resource. If it said this is just how much they produce, then it's output.
Neil
Shaikh, correct me if I'm wrong and Bablu I'll try to do the problem by 7:30 EST
Neil
Dude Bablu I think there's something wrong either with the question or the way you set that problem up
Neil
Cuz both countries can't specialize in both things
Neil
where is the following table?
ian
Figistan workers 10.........5 Blah Workers 30.............. 10
Neil
Neil Rawat time is not given in the question it's only the quantity of baskets of fruits and timber produced
The
The question says the labour force is 1,200.
The
i don.t understand plz explain esaily
Saifullah Reply
which 1u don't understand
ubong
marginal cost for what
Xasan
definition of economics
Abdal
Marginal cost is the additional increase in quantity produced as a result of increasing total cost
The
MC=dTC/dQ i.e change in total cost as a result of change in quantity produced
The
What happens to the quantity of dollars when the demand for it increases and supply decreases? Does the quantity or volume remain the same?
Anamaya
price of dollars will increase
Harsh
what are the principles of economics
Gajendra Reply
Economics is a social science that studies how people satisfy unlimited wants with scarce resources. It involves the analysis of choice and trade through the use of intuitive graphs and mathematical elements. The discipline is divided into two sections: microeconomics (micro) and macroeconomics(macr
Zain
micro and macro principles
Souley
I want to know about microeconomics principles
Gajendra
micro study economics partly eg hw mankind's makes decisions
Souley
explain clearly
Gajendra
it focuses on the actions of Individual agent within an economy like households,business etc
Souley
I understand
Gajendra
good
Souley
hellow guys
Paul
hi
Souley
hi
Gajendra
Hi
Souley
how are you guys doing
The
Helloooooo
Steven
Hi
Souley
Economics is difficult
The
yes, you can say but the positive thinkers and doers can not say like it.
Gajendra
Yeah. I'm pessimistic
The
and I procrastinate too much
The
is true
Souley
yea hello
Kojo
what's the scope for an economist?
Aman
I'm having exams soon but I barely know the concepts, monopoly is difficult
Steven
I can help with assignments
Nhamo
Gajendra or anybody can you advice me on how I can improve on studying Economics
The
should I read a topic everyday. it will be difficult because I have other courses
The
what's unemployment
Souley Reply
increase in inflation
Zain
increase in jobless peaople
Zain
who are capable of doing job
Zain
hi
Vijay
hi
Zain
distinguish between substitution effect and income effect
albert Reply
Elucidate more on this please!
Moshood Reply
hello
Kojo
hi
Peter
cfgjgdxgfxfgddhtdg
Abdal
Hi
Anamaya
Hello
Darlington
hi
Abdal
Who is an economist
Darlington
Hi
Ihtisham
hi
Peter
hi
Abdal
yes
Fazal
still studying
sean
The substitution effect is the change in consumption patterns due to a change in the relative prices of goods.
Moshood
Income effect is the change in consumption patterns due to the change in purchasing power.
Moshood
still freshman studying at Tubman University
Emmanuel
db awlad 97ab ghir ghatchr7ou liya chno wa93 hna wachmn level hada wla ghan7iw chi wld 9ahba fikom
Brahim
hi
Chidi
hi
bola
hey
cherie
hlw
God
Hi
Owusu
Hi
Patricia
hi
Rod
hi
shaikh
what is agriculture?
Emmanuel
Srsly
Neil
Hi everyone.
Royal
Economic is a subject which study buying and selling.
Royal
can u elaborate more?
Dazy
it is the study of the wealth of of a nation
Adesina
It can also be defined as the social science that studies how the available scarce resources can be distributed to satisfy unlimited human want
Adesina
elo house !
Adesina
I ave a question too
Adesina
hi
Prtj
guys I have questions which I am not able to solve could you guys help me
Prtj
ask
kartik
what is economic about
Gene
What the difference between economics and economics education?
Rasaq
economics is all about natural resources and how they are distributed to satisfied human wants
Souley
Almsot the same
Steven
what z international trade
ntaate Reply
The exchange of produce and services among different countries.
Anamaya
the exchange of good & services across international boundaries
WILSON
conditions of international trade?
Nusrat
in a comparison of the stages of meiosis to the stage of mitosis, which stages are unique to meiosis and which stages have the same event in botg meiosis and mitosis
Leah Reply
Researchers demonstrated that the hippocampus functions in memory processing by creating lesions in the hippocampi of rats, which resulted in ________.
Mapo Reply
The formulation of new memories is sometimes called ________, and the process of bringing up old memories is called ________.
Mapo Reply
how do you find theWhat are the wavelengths and energies per photon of two lines
caroline Reply
The eyes of some reptiles are sensitive to 850 nm light. If the minimum energy to trigger the receptor at this wavelength is 3.15 x 10-14 J, what is the minimum number of 850 nm photons that must hit the receptor in order for it to be triggered?
razzyd Reply
A teaspoon of the carbohydrate sucrose contains 16 calories, what is the mass of one teaspoo of sucrose if the average number of calories for carbohydrate is 4.1 calories/g?
ifunanya Reply
4. On the basis of dipole moments and/or hydrogen bonding, explain in a qualitative way the differences in the boiling points of acetone (56.2 °C) and 1-propanol (97.4 °C), which have similar molar masses
Kyndall Reply
Calculate the bond order for an ion with this configuration: (?2s)2(??2s)2(?2px)2(?2py,?2pz)4(??2py,??2pz)3
Gabe Reply
Which of the following will increase the percent of HF that is converted to the fluoride ion in water? (a) addition of NaOH (b) addition of HCl (c) addition of NaF
Tarun Reply

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