The 22 cm radiowave emitted by hydrogen in interstellar space is due to the interaction called the hyperfine interaction in atomic hydrogen. What is the energy of the emitted wave ?

Options

A. `10^(-25)` J
B. `9xx10^(-23)J`
C. `9xx10^(-25)`J
D. `10^(-18)J`

Answer

B

Explanation

`lambda=22cm = 22xx10^(-2)m=2.2xx10^(-3)m`
Energy of the wave `=` Energy of the photon
`E=hv=(hc)/(lambda)=(6.6xx10^(-34)xx3xx10^(8))/(22xx10^(-3))`
`=3xx3xx10^(-34+3+8)=9xx10^(-23)J`