Question

Four point charges +5 mC, +2 mC, +10mC and +2 mC are kept at the corners of a square of side 10 cm. A charge q=+1mC is placed at its centre. Find the net force on q.

Answer 1

Answer:

Explanation:

Four point charges +5 mC, +2 mC, +10mC and +2 mC are kept at the corners of a square of side 10 cm. A charge q=+1mC is placed at its centre. Find the net force on q.

F = k q₁ q₂ /r²

Let say these charge +5 mC, +2 mC, +10mC and +2 mC  are place in this sequence then

+2 mC are on opposite diagonal & will cancel each other

Distance of center from Corners = 5√2 cm = (5√2/100) m

F = k q₁ q₂ /r²

Net repulsive force from one corner

= k 10 * 5 * 10⁻⁶ /50 * 10⁻⁴  - k 5 * 5 * 10⁻⁶ /50 * 10⁻⁴

= k 5 * 5 * 10⁻⁶ /50 * 10⁻⁴

= k /200

k = 9.0 x 10⁹ N

= 9.0 x 10⁹/200

= 4.5 * 10⁷ N/m²