Question

The wavelength of an electromagnetic radiation is
400 nm. Thus, the wave number will be equal to
(1) 2.5 x 104 cm-1
(2) 2.5 x 103 cm-1
(3) 2.5 x 105 cm-1
(4) 2.5 x 102 cm-1​

Answer 1

Answer:

plz mark me brainlist thank you

Answer 2

Given info : The wavelength of an electromagnetic radiation is  400 nm.

To find : the wave number will be equal to ..

solution : the wave number is the inverse of wavelength of an electromagnetic radiation.

i.e., $\textbf{wave number}=\bf{\frac{1}{wavelength}}$

here, the wavelength of electromagnetic wave = 400 nm

= 4 × 10⁻⁵ cm

now the wave number = $\frac{1}{4\times10^{-5}}=2.5\times10^{4}cm^{-1}$

therefore the wave number of the given electromagnetic radiation is 2.5 × 10⁴ cm⁻¹. hence, the correct option is (1`).