Question

The sum of two point charges is 7uc.
They repel each other with a force of 1 N when kept 30 cm
apart in free space. Calculate the value of each charge.
​

Answer 1

Answer:

Let one of two charges isxμC

Therefore other charge will be(7−x)μC

By Columb's law

F=

4πϵ

0

1

r

2

q

1

q

2

1=9×10

9

×

(0.3)

2

(x×10

−6

(7−x)×10

−6

)

9×10

−2

=9×10

4−12

×(7−x)

10=x(7−x)

∴x

2

−7x+10=0⇒(x−2)(x−3)=0

x=2μCor5μC

Therefore, charges are 2μC and 5μC

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