BITSAT 2015
- Exam
- BITSAT
- Year
- 2015
- Subject
- Physics
- Chapter
- Magnetic Effects of Current
BITSAT 2015 · Physics · Magnetic Effects of Current
Two particles X and Y having equal charges, after being accelerated...
Two particles and having equal charges, after being accelerated through the same potential difference, enter a region of uniform magnetic field and describe circular paths of radii and , respectively. The ratio of masses of and is
Options
- A
- B
- C
- D
Correct answer
C.
Step-by-step solution
When a charge particle is allowed to move in a uniform magnetic field, then it describes spiral or circular path
\begin{array}{l}
\text{ Centripetal force, } \frac{\mathrm{mv}^{2}}{\mathrm{R}}=\mathrm{qvB} \quad \therefore \\
\mathrm{v}=\left(\frac{\mathrm{qB}}{\mathrm{m}} \mathrm{R}\right) \\
\text{ Hence, } \sqrt{\frac{2 \mathrm{q} \mathrm{V}}{\mathrm{m}}}=\left(\frac{\mathrm{qB}}{\mathrm{m}}\right) \mathrm{R}\left[\because \mathrm{V}=\sqrt{\frac{2 \mathrm{qV}}{\mathrm{m}}}\right] \\
\Rightarrow \mathrm{R}=\left(\frac{2 \mathrm{mV}}{\mathrm{q}}\right)^{1 / 2} \times \frac{1}{\mathrm{~B}} \\
\text{ or, } \mathrm{m} \propto \mathrm{R}^{2}
\end{array}
and are constant