Question

solve this of chapter electrostatics

Answer 1

Tcos∅ = mg { vertical tension component balance with weight ---(1)

Tsin∅ = KQ²/x² = Q²/4π€x² { horizontal tension component balance with electrostatics force } ------(2)

now, divide (2) by (1)

Tsin∅/Tcos∅ = Q²/4π€x²/mg

tan∅ = Q²/4π€x²mg

now,

T = mg/cos∅ = KQ²/x²sin∅

T= KQ²/x² sin∅ we take
sin∅ = x/L

now,
T = KQ²/x².x/L = Q²L/4π€x³