MCQ
An electron is accelerated through a potential difference of $1000$ volts. Its velocity is nearly
- A$3.8 \times {10^7}m/s$
- B$1.9 \times {10^6}m/s$
- ✓$1.9 \times {10^7}m/s$
- D$5.7 \times {10^7}m/s$
✓
Answer
Correct option: C.
$1.9 \times {10^7}m/s$
c
(c) If the voltage given is $V$, then the energy of electron
$\frac{1}{2}m{v^2} = eV$
(c) If the voltage given is $V$, then the energy of electron
$\frac{1}{2}m{v^2} = eV$
$\Rightarrow v = \sqrt {\frac{{2eV}}{m}} $
$ = \sqrt {\frac{{2 \times 1.6 \times {{10}^{ - 19}} \times 1000}}{{9.1 \times {{10}^{ - 31}}}}} = 1.875 \times {10^7}$$ \approx 1.9 \times {10^7}m/s$
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