Structure Of Atom Ques 60
60. 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}$ ?
[2003]
(a) $3 \times 10^{7}$
(b) $2 \times 10^{-25}$
(c) $5 \times 10^{-18}$
(d) $4 \times 10^{1}$
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Answer:
Correct Answer: 60.(d)
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 $4 \times 10^{1}$
BETA
