Question

The wavelength difference of light waves of wave numbers $ 2\times {{10}^{6}}\,/m $ and $ 2.25\times {{10}^{6}}/m $ is

• A. $ 0.556\,\times {{10}^{-6}}\,m $
• B. $ 0.0556\,\times {{10}^{6}}\,m $
• C. $ 0.0556\,\times {{10}^{-6}}\,m $
• D. $ 0.556\,\times {{10}^{6}}\,m $

Answer 1

Answer: (C)

$ \lambda =\frac{1}{2\times {{10}^{6}}}-\frac{1}{2.25\times {{10}^{6}}} $ $ =\frac{2.25-2}{2\times 2.25\times {{10}^{6}}} $ $ =\frac{0.25}{2\times 2.25\times {{10}^{6}}} $ $ =0.0556\times {{10}^{-6}}m $