- anonymous

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- katieb

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- anonymous

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- anonymous

- dan815

ok yep?

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- dan815

what is the question

- anonymous

so when i put all the values in the calc i dont get excat answer as tht

- dan815

http://www.wolframalpha.com/input/?i=4.14*10^-15+*3*10^8%2F2.55

- dan815

seems to be right

- anonymous

no i mean the answer is right but this is what i get when i put in the excat value

- arindameducationusc

what do you get?

- anonymous

4.8705*10^-7

- arindameducationusc

okay lets do by this way.....

- arindameducationusc

multiply by 4.14*3 . and in powers of 10, add -15 and 8, we get -7, isn't it

- anonymous

ok

- arindameducationusc

now 4.14*3 we get 12.4, now divide it by 2.55.

- arindameducationusc

so total we have 4.87 * 10^-7, isn't it?
And you have a problem that it is 487, right?

- anonymous

ok

- anonymous

Nanometer is 10^-9, the answer you got was 10^-7, so just some need to do conversion and you get the numbers.

- arindameducationusc

now listen carefully 1nm=10^-9m, right?
so,when we have 4.87*10^-7 if we take it to nanometer, 100 is multiplied to 4.87

- arindameducationusc

and 100 is divided in 10th power to make it to nanometer.....

- arindameducationusc

so, you get 487*10^-9, Got it?

- anonymous

is their a single number i can just times by

- arindameducationusc

I didn't get you, single number?

- anonymous

yea like when we have somthing in grams we just divide by 1000 to get in kg

- anonymous

0.000000001

- arindameducationusc

yes, yes

- arindameducationusc

10^-9 is 0.000000001
10^-7 is 0.0000001

- anonymous

in my data shhet i have to h values one in ev and the other in J which one to use?

- arindameducationusc

eV

- anonymous

how know for sho

- arindameducationusc

1eV=1.602*10^-19 J

- arindameducationusc

you can convert and write anyone.... its your choice....

- anonymous

if the question is in ev then i use ev right

- arindameducationusc

yes.. ofcourse

- arindameducationusc

But you can use Joules, but it will just become complicated...

- arindameducationusc

Got it?

- anonymous

yea

- anonymous

i hav e anotehr

- anonymous

i was doing these practive probs but wasnt getting the right answer doww

- anonymous

frequineces required for photoelectron emsiion in 400 THz

- arindameducationusc

ya, i will try ask

- anonymous

wavelength 500nm what is speed if excaping eletrons ?

- anonymous

tell me waht u get for speed

- arindameducationusc

from which orbit are the electrons escaping?

- anonymous

doesnt say anthing else

- anonymous

their was a work funstion 2.65*10^-19

- arindameducationusc

ya work function....

- arindameducationusc

Wait

- arindameducationusc

The minimum energy required to make an electron free from the metal is called the work function, right?

- anonymous

ye

- arindameducationusc

okay I got it....... use this

- arindameducationusc

hc/lambda=workfunction+K.E

- arindameducationusc

K.E is kinetic energy

- arindameducationusc

and K.E=1/2mv^2

- arindameducationusc

so you can get v from here.... rest all data given h,c,lambda,mass of electron and work function

- arindameducationusc

just plug in the values... you will get the answer. Got it?

- anonymous

Ek=hc/wavelenght

- anonymous

i tried i didnt get btw what u get

- arindameducationusc

so, do you have the answer with you? I will solve and ask you

- anonymous

yes

- arindameducationusc

9.33 * 10^21

- arindameducationusc

long calculation

- anonymous

its 5.40*10^5

- arindameducationusc

hmmm

- arindameducationusc

but the process is this way.... well I was of no use... sorry... I did my best....

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