Question

Two wave differ in frequency by 10^15 Hz. If one wave has

λ

= 4000

A



. What is

the wavelength of other wave​

Answer 1

Answer:

The wavelength of light is 4000pm or 4000×10−12m or 4000×10−9m.

The energy one photon is λhc=4×10−96.626×10−34×3×108=4.97×10−17.

The number of photons that will provide 1 J of energy is 4.97×10−171JJ=2.01×1018.

Answer 2

Given:

Difference in frequency = $10^-^1^5 Hz$

$\lambda _1 = 4000 \AA$

To find:

$\lambda_2$ ( wavelength of second wave )

Explanation:

We know that;

$f(frequency)= \frac{c}{\lambda }$

where c is the speed of light $c = 3\times 10^8m/s$

$\lambda _1 = 4\times 10^-^7m$

Substituting the values in the equation below:

$f_1 - f_2 = c (\frac{1}{\lambda_1 }- \frac{1}{\lambda _2})$

$10^1^5 = 3\times 10^8 (\frac{1}{\lambda _2}- \frac{1}{\ 4\times 10^-^7 })$

$0.33\times 10^7 = (\frac{1}{\lambda _2}- \frac{1}{\4\times 10^-^7 })$

$\frac{1}{\lambda _2} = 0.25\times 10^7+ 0.33 \times 10^7$  $=0.58\times 10^7$

$\lambda _2 = 1.72\times 10^-^7 m$