Question 943: Electrostats & Capacitance

Question

Four electric charges +q, +q, $$-$$ q and $$-$$ q are placed at the corners of a square of side 2L (see figure). The electric potential at point A, midway between the two charges + q and +q, is

Accepted Answer

Distance of point A from the two +q charges = L.
Distance of point A from the two Ã¢ÂÂq charges
$$ = \sqrt {{L^2} + {{\left( {2L} ight)}^2}}  = \sqrt 5 L$$
$$ 	herefore $$ $${V_A} = \left( {{{Kq} \over L} 	imes 2} ight) - \left( {{{Kq} \over {\sqrt 5 L}} 	imes 2} ight)$$
$$ = {{2Kq} \over L}\left[ {1 - {1 \over {\sqrt 5 }}} ight]$$
$$ = {1 \over {4\pi {\varepsilon _0}}}.{{2q} \over L}\left( {1 - {1 \over {\sqrt 5 }}} ight)$$

Answer

$${1 \over {4\pi {\varepsilon _0}}}{{2q} \over L}\left( {1 + \sqrt 5 } \right)$$

Answer

$${1 \over {4\pi {\varepsilon _0}}}{{2q} \over L}\left( {1 + {1 \over {\sqrt 5 }}} \right)$$

Answer

$${1 \over {4\pi {\varepsilon _0}}}{{2q} \over L}\left( {1 - {1 \over {\sqrt 5 }}} \right)$$

Answer

zero

Electrostats & Capacitance

Four electric charges +q, +q, $- q and -$ q are placed at the corners of a square of side 2L (see figure). The electric potential at point A, midway between the two charges + q and +q, is

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