Question

Find out the wavelength of violet light which has a frequency of $7.5\times {10}^{14}Hz$ ?

• A. $2.25\times {10}^{23}m$
• B. $2.5\times {10}^{5}m$
• C. $4\times {10}^{-7}m$
• D. $7.5\times {10}^{-7}m$
• E. $2.25\times {10}^{7}m$

Answer 1

The correct option is C $4\times {10}^{-7}m$

Given : $\nu =7.5\times {10}^{14}$ Hz

Speed of violet light (EM wave) $v=3\times {10}^8$ m/s

Thus wavelength of violet light $\lambda =\frac{v}{\nu }=\frac{3\times {10}^8}{7.5\times {10}^{14}}=4\times {10}^{-7}$ m