Question

If frequency of electromagnetic radiation is $7.5\times {10}^{12}$ Hz, then wavenumber of the radiation will be

• A. $2.5\times {10}^4{\text{m}}^{-1}$
• B. $4.5\times {10}^5{\text{m}}^{-1}$
• C. $4.5\times {10}^3{\text{m}}^{-1}$
• D. $2.5\times {10}^6{\text{m}}^{-1}$

Answer 1

The correct option is A $2.5\times {10}^4{\text{m}}^{-1}$

Answer (4)
$c=\nu \lambda$
$\frac{1}{\lambda }=\overline{\nu }=\frac{\nu }{c}=\frac{7.5\times {10}^{12}}{3\times {10}^8}$
$\overline{\nu }=2.5\times {10}^4{\text{m}}^{-1}$