JEE Main 2021 (Online) 20th July Morning Shift | Electrostatics Question 61 | Physics

JEE Main 2021 (Online) 20th July Morning Shift

MCQ (Single Correct Answer)

-1

A current of 5 A is passing through a non-linear magnesium wire of cross-section 0.04 m². At every point the direction of current density is at an angle of 60$$^\circ$$ with the unit vector of area of cross-section. The magnitude of electric field at every point of the conductor is :

(Resistivity of magnesium $$\rho$$ = 44 $$\times$$ 10^$$-$$8 $$\Omega$$m)

11 $$\times$$ 10^$$-$$5 V/m

11 $$\times$$ 10^$$-$$3 V/m

11 $$\times$$ 10^$$-$$7 V/m

11 $$\times$$ 10^$$-$$2 V/m

JEE Main 2021 (Online) 20th July Morning Shift

MCQ (Single Correct Answer)

-1

A certain charge Q is divided into two parts q and (Q $$-$$ q). How should the charges Q and q be divided so that q and (Q $$-$$ q) placed at a certain distance apart experience maximum electrostatic repulsion?

Q = 2q

Q = 4q

Q = 3q

Q = $${q \over 2}$$

JEE Main 2021 (Online) 18th March Morning Shift

MCQ (Single Correct Answer)

-1

An oil drop of radius 2 mm with a density 3g cm^$$-$$3 is held stationary under a constant electric field 3.55 $$\times$$ 10⁵ V m^$$-$$1 in the Millikan's oil drop experiment. What is the number of excess electrons that the oil drop will possess? (consider g = 9.81 m/s²)

48.8 $$\times$$ 10¹¹

1.73 $$\times$$ 10¹⁰

17.3 $$\times$$ 10¹⁰

1.73 $$\times$$ 10¹²

JEE Main 2021 (Online) 16th March Evening Shift

MCQ (Single Correct Answer)

-1

Find out the surface charge density at the intersection of point x = 3 m plane and x-axis, in the region of uniform line charge of 8 nC/m lying along the z-axis in free space.

0.424 nC m^$$-$$2

4.0 nC m^$$-$$2

47.88 C/m

0.07 nC m^$$-$$2

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