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15/08/2021 12:41 pm
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Calculate the velocity of ejected electron from the metal surface when light of frequency 2 × 1015 Hz fall on the metal surface and the threshold frequency is 7 × 1014 Hz for metal?
(a) 1.37 × 106
(b) 1.26 × 106
(c) 1.45 × 107
(d) 1.37 × 107
1 Answer
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15/08/2021 12:47 pm
(a) 1.37 × 106
Explanation:
\(\frac{1}{2}mv^2\) = hv - hv0
⇒ \(\frac{1}{2}mv^2\) = h(v - v0)
⇒ v = \(\sqrt{\frac{2h}{m}(v - v_0)}\)
= \(\sqrt{\frac{2 \times 6.6 \times 10^{-34}}{9.1 \times 10^{-31}}(2 \times 10^{15} - 7 \times 10^{14})}\)
= 1.37 x 106 ms-1
This post was modified 3 years ago by admin