So the energy of a photon is :
E = (h c )/ f
E: energy
h: constant 6.63 * 10^(-34)
C: constant 3 * 10^(8)
f: wavelength
thus if we have 75 kV of E
f = hc / E = 6.63 * 10 ^(-34) * 3 * 10^(8)
--------------------------------------
75 * 10^3 * 1.6 * 10^(-19)
Then the answer should be 1.6575 * 10^(-11)
But the solution is 16.6pm
I dont get it!!
2007-03-26 01:08:01 · 6 answers · asked by sunny 4 in Science & Mathematics ➔ Physics
f in this case represents lambda, too.
2007-03-26 01:24:37 · update #1
1 pm (Picometre) = 1 x 10^-12 metres
You have the right answer......
1.6575 x 10^-11 = 16.575 x 10^-12
They have just rounded up to 1 decimal place......i.e.
16.575 rounded up to 1dp = 16.6 x 10^-12 = 16.6 pm
2007-03-26 01:56:11 · answer #1 · answered by Doctor Q 6 · 0⤊ 0⤋
attempt writing each formula 15 situations. this might desire to help with the memmorization. additionally, lots of physics formulae could be derived, so with a splash calculus, you in basic terms might desire to keep in mind some equations.
2016-10-20 11:40:16 · answer #2 · answered by Anonymous · 0⤊ 0⤋
Units!
The value that you are using for Planck's constant is in Joule.seconds. You are quoting the energy in KeV
One of 'em has got to be converted!
2007-03-26 01:32:13 · answer #3 · answered by lunchtime_browser 7 · 0⤊ 0⤋
You've gotten the formula mixed up somewhere
E = h*c/lamda = h*f
EDIT: A ha, sorry didn't see the bit about f also being wavelength, apologies.
2007-03-26 01:20:06 · answer #4 · answered by dudara 4 · 0⤊ 0⤋
dudara's ans is ****....u got it right man...... 1.675 * 10^-11 = 16.6 * 10^-12 = 16.6 pm(picometer)...got it....1 pm = 1*10^-12......
2007-03-26 02:00:34 · answer #5 · answered by ashwin parihar 2 · 0⤊ 0⤋
Don't worry try another question....
2007-03-26 01:20:57 · answer #6 · answered by Aditya K 1 · 0⤊ 1⤋