A charge of #7 C# is at the origin. How much energy would be applied to or released from a # 9 C# charge if it is moved from # (2 ,-2 ) # to #(2 ,-1 ) #?

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Answer 1 · 2018-06-24T09:44:15

#335.66 * 10^9 J # of energy is relesed

As energy is scalar, only the distance of charges from origin are considered.

#U_i = 1/(4piepsilon_0) (7*9)/sqrt8#

and

#U_f = 1/(4piepsilon_0) (7*9)/sqrt5#

#"Work done by external force" = U_f - U_i#

#rArr"Work done by external force" = 1/(4piepsilon_0) (7*9)/sqrt5 - 1/(4piepsilon_0) (7*9)/sqrt8#

#rArr"Work done by external force"="Energy released/gained"= -335.66 * 10^9 J#

As work done is negetive, energy is released.