Structure of Atom - Result Question 6
####6. 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 $8 \times 10^{15} s^{-1}$ ?
(a) $3 \times 10^{7}$
(b) $2 \times 10^{-25}$
(c) $5 \times 10^{-18}$
(d) $4 \times 10^{1}$
[2003]
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Solution:
- (d) $E=h v=\frac{h c}{\lambda}$ or $\lambda=\frac{c}{v}$
$\Rightarrow \lambda=\frac{3 \times 10^{8}}{8 \times 10^{15}}=3.75 \times 10^{-8} m$
In nanometer $\lambda=3.75 \times 10$ which is closest to $4 \times 10^{1}$
