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Physics · PYQ NEET UG 2017
हिन्दीThe photoelectric threshold wavelength of silver is \( 3250 \times 10^{-10}\text{ m} \). The velocity of the electron ejected from a silver surface by ultraviolet light of wavelength \( 2536 \times 10^{-10}\text{ m} \) is: (Given: \( h = 4.14 \times 10^{-15}\text{ eVs} \) and \( c = 3 \times 10^8\text{ ms}^{-1} \))
Correct answer · Option 1
\( \approx 6 \times 10^5\text{ ms}^{-1} \)
Explanation
Using Einstein's photoelectric equation, \( \frac{1}{2}mv^2 = hc(\frac{1}{\lambda} - \frac{1}{\lambda_0}) \). Substituting the given values yields velocity \( v \approx 6 \times 10^5\text{ ms}^{-1} \).
