How much energy is contained in 1 mol of each of γ -ray photons with a wavelength of 2.72×10−5 nm.

Question

joannablackwelder · Answer

@abb0t

joannablackwelder · Answer

I got 4.40 x 10^12 J. Can anyone confirm?

joannablackwelder · Answer

@aaronq

abb0t · Answer

Use the equation: $\sf \color{red}{E = hv = h\frac{c}{\lambda}}$
this is when you're referring to a photon, which you are here:

c = speed of light = 3.0 x 10$^8 \frac{m}{s}$
h = planks constant = 6.626 x 10$^{-34}$ J • s
$\lambda$ = wavelength (make sure it is in meters to match with units for speed of light).

Hence, convert nm $\rightarrow$ m

1 m = 10$^{9}$nm

joannablackwelder · Answer

Yeah, I did that. Did you get a different answer?

joannablackwelder · Answer

@abb0t

aaronq · Answer

After you use the equation abb0t provided (planck's equation gives the energy of one photon) you need to multiply by avogadro's number.

joannablackwelder · Answer

Thanks, @aaronq, I did that too. :-) Do you get 4.40 x 10^12 J too?

aaronq · Answer

yes, it works out to that number

joannablackwelder · Answer

Thanks so much!