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Planck's quantum theory
Appears in
Concepts tested here
- Energy and wavelength
- Energy of a photon
All Questions
2014 AIPMT 1 question
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Calculate the energy in joule corresponding to light of wavelength 45 nm: (Planck's constant h = $6.63\times10^{-34}$ Js; speed of light c = $3\times10^8$ $ms^{-1}$)$E = \frac{hc}{\lambda} = \frac{6.63\times10^{-34}\times3\times10^8}{45\times10^{-9}}$
$E = 4.42\times10^{-18}$ J
2011 AIPMT-PRE 1 question
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The energies $E_1$ and $E_2$ of two radiations are 25 eV and 50 eV respectively. The relation between their wavelengths i.e. $\lambda_1$ and $\lambda_2$ will beEnergy of a photon: $E = \frac{hc}{\lambda}$, so $E \propto \frac{1}{\lambda}$
$\frac{E_1}{E_2} = \frac{\lambda_2}{\lambda_1}$
$\frac{25}{50} = \frac{\lambda_2}{\lambda_1}$
$\frac{\lambda_2}{\lambda_1} = \frac{1}{2}$
$\lambda_1 = 2\lambda_2$