Question 163 of 276
In an experiment, electrons are accelerated, from rest, by applying a voltage of . Calculate the radius of the path if a magnetic field is then applied. [Charge of the electron
Mass of the electron
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Answer: (D)
Radius of the path (r) is given by
\begin{aligned}
\mathrm{r} &=\frac{\sqrt{2 \mathrm{mk}}}{\mathrm{eB}} \quad(\because \mathrm{p}=\mathrm{mv}=\sqrt{2 \mathrm{mk}}) \\
&=\frac{\sqrt{2 \mathrm{meV}}}{\mathrm{eB}} \quad(\because \mathrm{k}=\mathrm{eV}) \\
\mathrm{r} &=\frac{\sqrt{\frac{2 \mathrm{~m}}{\mathrm{e}} \mathrm{V}}}{\mathrm{B}}=\frac{\sqrt{\frac{2 \times 9.1 \times 10^{-31}}{1.6 \times 10^{-19}}(500)}}{100 \times 10^{-3}}
\end{aligned}
\begin{aligned}
\mathrm{r} &=\frac{\sqrt{2 \mathrm{mk}}}{\mathrm{eB}} \quad(\because \mathrm{p}=\mathrm{mv}=\sqrt{2 \mathrm{mk}}) \\
&=\frac{\sqrt{2 \mathrm{meV}}}{\mathrm{eB}} \quad(\because \mathrm{k}=\mathrm{eV}) \\
\mathrm{r} &=\frac{\sqrt{\frac{2 \mathrm{~m}}{\mathrm{e}} \mathrm{V}}}{\mathrm{B}}=\frac{\sqrt{\frac{2 \times 9.1 \times 10^{-31}}{1.6 \times 10^{-19}}(500)}}{100 \times 10^{-3}}
\end{aligned}
