Dual Nature of Radiation and Matter - Result Question 63

67. Kinetic energy of an electron, which is accelerated in a potential difference of $100 V$ is

[1995]

(a) $1.6 \times 10^{-17} J$

(b) $1.6 \times 10^{-19} J$

(c) $1.6 \times 10^{-21} J$

(d) $1.6 \times 10^{-25} J$

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Answer:

Correct Answer: 67. (a)

Solution:

  1. (a) Potential difference $(V)=100 V$. The kinetic energy of an electron $=1 eV=1 \times(1.6 \times 10^{-19})$ $=1.6 \times 10^{-19} J$. Therefore kinetic energy in 100 volts $=(1.6 \times 10^{-19}) \times 100=1.6 \times 10^{-17} J$. K.E. $=qV$

$=1.6 \times 10^{-19} \times 100 J=1.6 \times 10^{-17}$