Question

Find the force between two charges when they are brought in contact and separated by 4cm apart, charges are 2nC and -1nC, in μN. ​

Answer 1

Correct Question

Find the force between two charges when they are brought in contact and separated by 4cm apart, charges are +2μC and -1μC.

Solution-

Given that, two charges carrying a charge of +2μC and -1μC and distance between both the charges is 4 cm i.e. 0.04 m.

We have to find the force between two charges.

Let us assume that the charge q1 is carrying a charge of +2μC and charge q2 is carrying a charge of -1μC.

Since, both the charges are brought in contact with each other. So,

Charge on both the charges is given by:

= (Charge on q1 + Charge on q2)/2

= (+2 - 1)/2

= +1/2

= +0.5

Both of them are carrying a charge of +0.5 μC.

Now,

F = k (q1 q2)/r²

Where, k = 9×10^9 Nm²C-²

Substitute the known values,

→ F = 9 × 10^9 (0.5 × 0.5)/(0.04)²

→ F = (9 × 10^9 × 0.25)/0.0016

→ F = (2.25 × 10^13)/16

→ F = 0.14 × 10^13

→ F = 1.4 × 10^12

Therefore, the force between both the charges is 1.4 × 10^12 N.