1
WB JEE 2021
MCQ (Single Correct Answer)
+1
-0.25
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WB JEE 2021 Physics - Electrostatics Question 16 English
The variation of electric field along the Z-axis due to a uniformly charged circular ring of radius a in XY-plane as shown in the figure. The value of coordinate M will be
A
$${1 \over 2}$$
B
$$\sqrt 2 $$
C
1
D
$${1 \over {\sqrt 2 }}$$
2
WB JEE 2021
MCQ (Single Correct Answer)
+1
-0.25
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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
A
$${q \over {4\pi {\varepsilon _0}}}\left( {{1 \over a} - {1 \over b}} \right)$$
B
$${q \over {4\pi {\varepsilon _0}}} - {1 \over a}$$
C
$${q \over {4\pi {\varepsilon _0}}}\left( {{1 \over R} - {1 \over a}} \right)$$
D
$${q \over {4\pi {\varepsilon _0}}} - {1 \over R}$$
3
WB JEE 2021
MCQ (Single Correct Answer)
+1
-0.25
Change Language
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
A
$${{5\sigma } \over {2{\varepsilon _0}}}\widehat j$$
B
$$ - {{7\sigma } \over {2{\varepsilon _0}}}\widehat j$$
C
$${\sigma \over {2{\varepsilon _0}}}\widehat j$$
D
$${{5\sigma } \over { - 2{\varepsilon _0}}}\widehat j$$
4
WB JEE 2021
MCQ (Single Correct Answer)
+1
-0.25
Change Language
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
A
possible only if q3 is negative.
B
possible only if q3 is positive.
C
possible irrespective of the sign of q3.
D
not possible at all.
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