COMEDK 2023 Morning Shift | Electrostatics Question 1 | Physics

Two point charges $$20 \mu \mathrm{C}$$ and $$-10 \mu \mathrm{C}$$ are separated by a distance of $$1 \mathrm{~m}$$ in air. At what point on the line joining the two charges, the electric potential is zero.

$$0.5 \mathrm{~m}$$ from the charge $$10 \mu \mathrm{C}$$

$$0.76 \mathrm{~m}$$ from the charge $$20 \mu \mathrm{C}$$

$$0.67 \mathrm{~m}$$ from the charge $$20 \mu \mathrm{C}$$

$$0.25 \mathrm{~m}$$ from the charge $$10 \mu \mathrm{C}$$

COMEDK 2023 Evening Shift

MCQ (Single Correct Answer)

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A spherical metal ball of density '$$\rho$$' and radius '$$r$$' is immersed in a liquid of density '$$\sigma$$'. When an electric field is applied in the upward direction the metal ball remains just suspended in the liquid. Then the expression for the charge on the metal ball is :

$$q=\frac{\left[\frac{4}{3} \pi r^3 \rho g\right]}{\sigma E}$$

$$q=\frac{\left[4 \pi r^3(\rho-\sigma) g\right]}{3 E}$$

$$q=\frac{\left[4 \pi r^2 \rho g\right]}{\sigma E}$$

$$q=\frac{\left[4 \pi r^2(\rho-\sigma) g\right]}{E}$$

COMEDK 2023 Evening Shift

MCQ (Single Correct Answer)

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PQRS is square of side $$1 \mathrm{~m}$$. A charge of $$100 \mu \mathrm{C}$$ is placed at the centre of the square. Then the work done to take $$3 \mu \mathrm{C}$$ charge from the corner $$\mathrm{P}$$ to the corner $$\mathrm{R}$$.

$$9 \sqrt{2} \times 10^5 \mathrm{~J}$$

$$4.5 \times 10^5 \mathrm{~J}$$

Zero

$$1.8 \times 10^5 \mathrm{~J}$$

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