Question

Calculate energy of photon of light travelling having frequency for 3 * 10^15 sec^-1.

Answer 1

Answer:

e = 1.989 × 10⁻¹⁸ J

Explanation:

Given :

$\displaystyle \text{Frequrency(v) = 3\times10^{15} \ Hz }$

We have to find energy ( e )

From planck ' s energy equation

we have

e = h v

where e = energy of photon

h =  planck ' s constant

value of h = 6.03 × 10⁻³⁴ J sec

Put the value here we get

e = 6.63 × 10⁻³⁴ × 3 × 10¹⁵ J

e = 19.89 × 10⁻¹⁹ J

e = 1.989 × 10⁻¹⁸ J

Thus we get energy of photon.

Answer 2

$\underline{\textbf{\large{Explanation:}}}$

we know,

energy of photon (E) = h (planks constant) x f (frequency)

here,

speed of light (c) = λ(wavelength) X f (frequency)

Divide by λ on both the sides,

$\sf\frac{c}{λ} = \frac{λ.f}{λ }$

$\sf\frac{c}{λ} = f$

therefore,

$\sf E = \frac{hc}{λ}$

but here we have already given given a frequency,so the formula we need to use,

$\sf \boxed{E = h. f}$

the value of Planck's constant is

$\sf h = 6.626 x 10^{-34}j.s$

so the Energy of photon,

E = h. f

$\sf{ = (6.626 x 10^{-34}) x (3 x 10^{15})}$

$\sf{ = 19.878 x 10^{-19} j}$

therefore the energy of photon is$\sf{ 19.878 x 10^{-19} j}$