Question

The value of Planck's constant is $6.63\times {10}^{-34}$ Js. The velocity of light is $3\times {10}^8$ m/sec. Which value is closest to the wavelength of a quantum of light with frequency of $8\times {10}^{15}se{c}^{-1}$ ?

• A. $5\times {10}^{-18}$ m
• B. $4\times {10}^{-8}$ m
• C. $3\times {10}^7$ m
• D. $2\times {10}^{-25}$ m

Answer 1

The correct option is B $4\times {10}^{-8}$ m

According to the relation,

$\nu =\frac{c}{\lambda }=\frac{3.0\times {10}^8}{\lambda }$

$\lambda =\frac{3.0\times {10}^8}{\nu }=\frac{3.0\times {10}^8}{8.0\times {10}^{15}}=3.75\times {10}^{-8}\approx 4.0\times {10}^{-8}m$

Hence, the correct option is $B$