The gravitational field in a region is given by: $\vec{E}=(5 N / k g) \hat{i}+(12 N / k g) \hat{j}$ If the…

The gravitational field in a region is given by: $\vec{E}=(5 N / k g) \hat{i}+(12 N / k g) \hat{j}$ If the potential at the origin is taken to be zero, then the ratio of the potential at the points $(12 \mathrm{~m}, 0)$ and $(0,5 \mathrm{~m})$ is :
  1. Zero
  2. 1
  3. $\frac{144}{25}$
  4. $\frac{25}{144}$

Solution

From question, $\mathrm{E}_{\mathrm{x}}=5 \mathrm{~N} / \mathrm{kg}$ and $\mathrm{E}_{\mathrm{y}}=12 \mathrm{~N} / \mathrm{kg}$ Gravitational potential $=$ Gravitational field $\times$ distance $\therefore \mathrm{V}_{(12 \mathrm{~m}, 0)}=\mathrm{E}_{\mathrm{x}} \times 12 \mathrm{~J} / \mathrm{kg}$ and $\mathrm{V}_{(0,5 \mathrm{~m})}=\mathrm{E}_{\mathrm{y}} \times 5 \mathrm{~J} / \mathrm{kg}$ (Given : potential at the origin is zero) $ \therefore \frac{V_{(12 \mathrm{~m}, 0)}}{\mathrm{V}_{(0,5 \mathrm{~m})}}=\frac{\mathrm{E}_{\mathrm{x}} \times 12}{\mathrm{E}_{\mathrm{y}} \times 5}=\frac{5 \times 12}{12 \times 5}=1 $

Asked in: JEE Main 2013 (25 Apr Online)

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