Chemistry and Math combineee!?

Question

Formula E=hc/λ
c=3.00x10^8
h=6.62x10^-34
λ=5x10^-11

After the solution is found, adjust it to 10^-20 for graphing.
I get to this point, but I don't know how to adjust it to 10^-20.
Please help me. Explain thoroughly, not just and answer.

Answer 1

So...
E = (6.62x10^-34) (3.00x10^8) / (5x10^-11)
E = 3.972x10^-15

3.972x10^-15 = 397200x10^-20
(just move the decimal point 5 places right)

Answer 2

This is just a guess.

When you multiply everything out, you get

E=3.972x10^-15

This is in its simplest scientific notation form because there is only one number before the decimal.

If you move the decimal point to the right one place, you must drop the power by one in order to keep the number at the same value.

So basically we'll just move the decimal place 5 places to the right. When we do this, we have to drop the power by 5. (-15 -5 = -20)

3.972x10^-15
39.72x10^-16
397.2x10^-17
3,972x10^-18
39,720x10^-19
397,200x10^-20

So I think the number you're looking for is "397,200x10^-20"

I'm not sure how you would use this "for graphing" so I can't help you there but that's my best guess for the adjustment part of the problem.

Answer 3

Always include units to make the conversion clear. c is in m/s. h is in Joule-seconds. lambda is in meters (I think???) though this is a very short wavelength - only half an angstrom - an x-ray? Put everything together to get hc/lambda = 3.97x10^-15 Joule seconds meters/second per meter. So the meters and seconds cancel, and the answer is 3.97 x 10^-15 Joules. Not much to graph here - there's only one point! But if you multiply by 10^20, the answer is 397200 in units of 10^-20 Joules
(39700x10^-20Joules = 3.97x10^-15 Joules)
P.S. Often the energy for photons is written in electron-volts, eV. To get from Joules to eV, divide the number by the charge on the electron, 1.6e-19. This gives a convienient result of 24825 eV = 24.825 keV

Answer 4

Formula E=hc/λ
c=3.00x10^8
h=6.62x10^-34
λ=5x10^-11

E = hc/λ
E = [6.62*10^(-34)](3.00*10^8)/[5*10^(-11)]
E = (6.62*3/5)*10^(-34+8+11)
E = 3.972*10^(-15)

To adjust this:

E = 3.972*10^(-15)
E = 3.97200*10^(-15)
E = 397,200*10^(-20)

We moved the decimal point 5 places to the right.