# Ultraviolet radiation has a frequency of 6.8×1015 hz. what is the energy associated with this frequency?

###### Question:

## Answers

Use Planck's equation (E=hv) to solve. where frequency (v) of ultrviolet radiation is 6.8 × 1015 1/s. The variable h is a constant equal to 6.63 × 10-34 J·s

E= (6.8 × 1015 1/s)x(6.63 × 10-34 J·s)

The energy associated with blue light is [tex]49.65\times 10^{-20}J[/tex]

Explanation:

To calculate the energy of the light for a given frequency, we use the equation given by Planck, which is:

[tex]E=h\nu[/tex]

where,

E = energy of the light

h = Planck's constant = [tex]6.62\times 10^{-34}Js[/tex]

[tex]\nu[/tex] = frequency of the light = [tex]7.5\times 10^{14}s^{-1}[/tex]

Putting values in above equation, we get:

[tex]E=6.62\times 10^{-34}Js\times 7.5\times 10^{14}s^{-1}=49.65\times 10^{-20}J[/tex]

Hence, the energy associated with blue light is [tex]49.65\times 10^{-20}J[/tex]

A) c = 3 x 10^8 m/s

f = 7.15 x 10^14 Hz

c = λ x f (=) λ = 3 x 10^8 / 7.15 x 10^14 = 4.19 x 10^-7 m = 419.6 nm

B) E = h f

H = Planck's constant = 6.63 x 10^-34 J/s

E = 6.63 x 10^-34 x 7.15 x 10^14 = 4.74 x 10^-19 J