WB JEE 2021 | Electrostatics Question 18 | Physics

A metal sphere of radius R carrying charge q is surrounded by a thick concentric metal shell of inner and outer radii a and b, respectively. The net charge on the shell is zero. The potential at the centre of the sphere, when the outer surface of the shell is grounded will be

$${q \over {4\pi {\varepsilon _0}}}\left( {{1 \over a} - {1 \over b}} \right)$$

$${q \over {4\pi {\varepsilon _0}}} - {1 \over a}$$

$${q \over {4\pi {\varepsilon _0}}}\left( {{1 \over R} - {1 \over a}} \right)$$

$${q \over {4\pi {\varepsilon _0}}} - {1 \over R}$$

WB JEE 2021

MCQ (Single Correct Answer)

-0.25

Three infinite plane sheets carrying uniform charge densities $$-$$ $$\sigma$$, 2$$\sigma$$, 4$$\sigma$$ are placed parallel to XZ-plane at Y = a, 3a, 4a respectively. The electric field at the point (0, 2a, 0) is

$${{5\sigma } \over {2{\varepsilon _0}}}\widehat j$$

$$ - {{7\sigma } \over {2{\varepsilon _0}}}\widehat j$$

$${\sigma \over {2{\varepsilon _0}}}\widehat j$$

$${{5\sigma } \over { - 2{\varepsilon _0}}}\widehat j$$

WB JEE 2021

MCQ (Single Correct Answer)

-0.25

Two point charges +q₁ and +q₂ are placed a finite distance d apart. It is desired to put a third charge q₃ in between these two charges, so that q₃ is in equilibrium. This is

possible only if q₃ is negative.

possible only if q₃ is positive.

possible irrespective of the sign of q₃.

not possible at all.

WB JEE 2020

MCQ (Single Correct Answer)

-0.25

As shown in the figure, a point charge q₁ = + 1 $$ \times $$ 10^-6 C is placed at the origin in xy-plane and another point charge q₂ = + 3 $$ \times $$ 10^-6 C is placed at the coordinate (10, 0).

WB JEE 2020 Physics - Electrostatics Question 37 English

WB JEE 2020 Physics - Electrostatics Question 37 English

In that case, which of the following graph(s) shows most correctly the electric field vector in E_x in x-direction?

WB JEE 2020 Physics - Electrostatics Question 37 English Option 1

WB JEE 2020 Physics - Electrostatics Question 37 English Option 2

WB JEE 2020 Physics - Electrostatics Question 37 English Option 3

WB JEE 2020 Physics - Electrostatics Question 37 English Option 4

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