Two small charged spheres having charges of 1× 10- 7C and 2× 10- 7C are placed 20 cm apart in air. The force between them is

Question

Two small charged spheres having charges of 1× 10- 7C and 2× 10- 7C are placed 20 cm apart in air. The force between them is (A)  4.5× 10- 2N (B) 4.5× 10- 3N (C) 5.4× 10- 2N (D) 5.4× 10- 3N

Tardigrade Admin · Accepted Answer

Here, q1=1× 10- 7C, q2=2× 10- 7C As F=(q1 q2/4 π (ϵ )0 r2)=(9 × (10)9 × 1 × (10)- 7 × 2 × (10)- 7/(20 × (10)- 2)2)=4.5× (10)- 3 N

Q. Two small charged spheres having charges of $1 \times 1 0^{- 7} C$ and $2 \times 1 0^{- 7} C$ are placed $20$ $c m$ apart in air. The force between them is

$4.5 \times 1 0^{- 2} N$

$4.5 \times 1 0^{- 3} N$

$5.4 \times 1 0^{- 2} N$

$5.4 \times 1 0^{- 3} N$

Here, $q_{1} = 1 \times 1 0^{- 7} C, q_{2} = 2 \times 1 0^{- 7} C$
As $F = \frac{q _{1} q _{2}}{4 π ( ϵ ) _{0} r ^{2}} = \frac{9 \times ( 10 ) ^{9} \times 1 \times ( 10 ) ^{- 7} \times 2 \times ( 10 ) ^{- 7}}{( 20 \times ( 10 ) ^{- 2} ) ^{2}} = 4.5 \times (10)^{- 3} N$

Q. Two small charged spheres having charges of 1×10−7C and 2×10−7C are placed 20 cm apart in air. The force between them is

4.5×10−2N

4.5×10−3N

5.4×10−2N

5.4×10−3N