An electron of mass m and a photon have same energy $\mathrm{E.}$ The ratio of de-Broglie wavelengths associated with them is:
($\mathrm{c}$ being velocity of light)

• Correct answer
  A

  $\frac{1}{\mathrm{c}}{\left(\frac{\mathrm{E}}{2\mathrm{m}}\right)}^{\frac{1}{2}}$
• B

  ${\left(\frac{\mathrm{E}}{2\mathrm{m}}\right)}^{\frac{1}{2}}$
• C

  $\mathrm{c}{\left(2\mathrm{m}\mathrm{E}\right)}^{\frac{1}{2}}$
• D

  $\frac{1}{\mathrm{c}}{\left(\frac{2\mathrm{m}}{\mathrm{E}}\right)}^{\frac{1}{2}}$

Hence, the correct answer is option: 'A'.