Question

The absorption spectrum of argon has a line at 515 nm. What is the energy of

this line? (The speed of light in a vacuum is 3.00 x 108 m/s, and Planck's

constant is 6.626 x 10-34 Jos.)

O A. 2.59 x 1027j

O B. 3.86 x 10-28 J

O C. 3.86 x 10-19 J

O D. 2.59 x 1018 J

Answer 1

OPTION C is correct

3.86 x 10-19 J

Step-by-step explanation:

Energy of the line can be calculated using below formula

E= h ν.................(1)

Where E= energy

h= plank constant= 6.626 10-34 J s

c=speed of light=3 x 108 m/s

But we know that Velocity V= = c / λ

Then substitute into equation (1) we have

E = h c / λ.............(2)

We can calculate our( hc ) in nm for unit consistency

h c =( 6.626 ×10^-34)x(3×108)

h c = (1.986 x 10-16 )

hc = 1.986 x 10-16 J nm then since our (hc) and λ are in the same unit , were good to go then substitute into equation(2)

E = h c / λ = (1.986 x 10-16) / 515

E = 3.86 x 10-19 J

Therefore, the Energy is 3.86 x 10-19 J