Question

White light forms a continuous spectrum of minimum wavelength $3800\mathring{A}$ corresponding to violet light and maximum wavelength $7800\mathring{A}$ corresponding to red light. The minimum and maximum frequencies of white light are ($c=3\times {10}^8$ m/s):

• A. $3.846\times {10}^{14}Hz,7.895\times {10}^{14}Hz$
• B. $4.5\times {10}^{14}Hz,4.65\times {10}^{14}Hz$
• C. $5.5\times {10}^{14}Hz,6.25\times {10}^{14}Hz$
• D. $4.78\times {10}^{14}Hz,5.4\times {10}^{14}Hz$

Answer 1

The correct option is A $3.846\times {10}^{14}Hz,7.895\times {10}^{14}Hz$

Minimum frequency $f_{min}=\frac{c}{{\lambda }_{max}}$

$=\frac{3\times {10}^8}{7800\times {10}^{-10}}$

$=3.846\times {10}^{14}Hz$

Maximum frequency $f_{max}=\frac{c}{{\lambda }_{min}}$

$=7.895\times {10}^{14}Hz$