Easy MCQ +4 / -1 PYQ · JEE Mains 2024

Two particles $X$ and $Y$ having equal charges are being accelerated through the same potential difference. Thereafter they enter normally in a region of uniform magnetic field and describes circular paths of radii $R_1$ and $R_2$ respectively. The mass ratio of $X$ and $Y$ is :

  1. A $\left(\frac{R_1}{R_2}\right)$
  2. B $\left(\frac{R_2}{R_1}\right)$
  3. C $\left(\frac{R_2}{R_1}\right)^2$
  4. D $\left(\frac{R_1}{R_2}\right)^2$ Correct answer

Solution

<p>$$\begin{aligned} & \mathrm{R}=\frac{\mathrm{mv}}{\mathrm{qB}}=\frac{\mathrm{p}}{\mathrm{qB}}=\frac{\sqrt{2 \mathrm{~m}(\mathrm{KE})}}{\mathrm{qB}}=\frac{\sqrt{2 \mathrm{mqV}}}{\mathrm{qB}} \\ & \mathrm{R} \propto \sqrt{\mathrm{m}} \\ & \mathrm{m} \propto \mathrm{R}^2 \\ & \frac{\mathrm{m}_1}{\mathrm{~m}_2}=\left(\frac{\mathrm{R}_1}{\mathrm{R}_2}\right)^2 \end{aligned}$$</p>

About this question

Subject: Physics · Chapter: Magnetic Effects of Current · Topic: Biot-Savart Law

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