Question

use the same equation as above to calculate the energy of uv light with wavelength 300. nm. (e = h c/λ, and h = 6.63 x 10^(-34) js, and c = 3.00 x 10^8 m/s). h c 1 2 e = ------- = -------------- = 3 λ 4 according to these calculations, uv has 5 than blue - violet light a. 6.63 x 10^(-34) js b. 3.00 x 10^8 m/s c. 300. nm d. 300. x 10^(-9) m e. 6.63 x 10^(-28) j f. 6.63 x 10^(-19) j g. higher energy h. lower energy i. got no energy, need coffee

Explanation:

Step1: Convert wavelength to SI unit

Given $\lambda = 300\ nm=300\times10^{-9}\ m$.

Step2: Substitute values into formula

Substitute $h = 6.63\times 10^{-34}\ Js$, $c = 3.00\times 10^{8}\ m/s$ and $\lambda=300\times 10^{-9}\ m$ into $E=\frac{hc}{\lambda}$. So $E=\frac{6.63\times 10^{-34}\times3.00\times 10^{8}}{300\times 10^{-9}}$.

Step3: Calculate the energy

$E=\frac{6.63\times 10^{-34}\times3.00\times 10^{8}}{300\times 10^{-9}}=\frac{6.63\times3.00}{300}\times10^{-34 + 8+9}=6.63\times 10^{-19}\ J$. Also, since energy of a photon is inversely - proportional to wavelength ($E=\frac{hc}{\lambda}$), and UV light has a shorter wavelength than blue - violet light, UV has higher energy.

Answer:

1. A. $6.63\times 10^{-34}\ Js$
2. B. $3.00\times 10^{8}\ m/s$
3. F. $6.63\times 10^{-19}\ J$
4. D. $300\times 10^{-9}\ m$
5. G. higher energy