NEET Chemistry Structure of Atom / परमाणु संरचना NEET PYQ-Structure of Atom

The value of Planck's constant is \[6.63\times {{10}^{-34}}Js\]. The velocity of light is \[3.0\times {{10}^{8}}m{{s}^{-1}}\]. Which value is closest to the wavelength in nanometers of a quantum of light with frequency of \[8\times {{10}^{15}}{{s}^{-1}}\]?                            [AIPMT 2003]

A)             \[4\times {{10}^{1}}\]

B)                  \[3\times {{10}^{7}}\]

C) \[2\times {{10}^{-25}}\]

D)      \[5\times {{10}^{-18}}\]

Correct Answer: A

Solution :

\[\therefore \] Frequency \[=\frac{c}{\lambda }=\frac{3\times {{10}^{8}}m\,{{s}^{-1}}}{8\times {{10}^{15}}\,{{s}^{-1}}}\]

\[=0.375\times {{10}^{-7}}\,m\]

\[=3.75\times {{10}^{1}}\,nm\,\approx \,4\times {{10}^{1}}\,nm\]