# Four equal point charges Q each are placed in the xy placed at (0, 2), (4, 2), (4, −2) and (0, −2). The work required to put a fifth charge Q at the origin of the coordinate system will be: (a) (b)   (c) (d)

## Question ID - 50281 :- Four equal point charges Q each are placed in the xy placed at (0, 2), (4, 2), (4, −2) and (0, −2). The work required to put a fifth charge Q at the origin of the coordinate system will be: (a) (b)   (c) (d)

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Potential at origin=

(Potential at

=KQ Work required to put a fifth charge Q at origin is equal to

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 A cylindrical plastic bottle of negligible mass is filled with 310 ml of water and left floating in a pond with still water. If pressed downward slightly and released, it starts performing simple harmonic motion at angular frequency . If the radius of the bottle is 2.5 cm then  close to: (density of water =103 kg/m3) (a) 5.00 rad s−1 (b) 1.25 rad s−1 (c) 3.75 rad s−1 (d) 7.95 rad s−1