Q143 / 150 · MHT CET 2020 (19 Oct Shift 2) · Physics
The escape velocity of a body from any planet whose mass is six times the mass of earth and radius is twice the radius of earth will be
$\left(\mathrm{V}_{e}=\right.$ escape velocity of a body from the earth's surface)
- Correct answerA$\sqrt{3} \mathrm{~V}_{\mathrm{e}}$
- B$2 \mathrm{~V}_{\mathrm{e}}$
- C$\frac{3}{2} \mathrm{~V}_{\mathrm{e}}$
- D$2 \sqrt{2} \mathrm{~V}_{\mathrm{e}}$
Solution
(D)
$\begin{aligned} \mathrm{V}_{\mathrm{e}} &=\sqrt{\frac{2 \mathrm{GM}}{\mathrm{R}}} \\ \mathrm{V}_{\mathrm{e}}^{\prime} &=\sqrt{\frac{2 \mathrm{G} \times 6 \mathrm{M}}{2 \mathrm{R}}} \\ &=\sqrt{\frac{2 \mathrm{GM}}{\mathrm{R}} \times 3} \\ &=\sqrt{3} \mathrm{~V}_{\mathrm{e}} \end{aligned}$
Hence, the correct answer is option: 'A'.