Question

If mass of electron is 9.1 into 10 raise to power minus 31 kg charge on the electron is 1.6 into 10 raise to power minus 19 coulomb and gravity is 9.8 metre per second square then the intensity of electric field required to balance the weight of an electron is

Answer 1

Given : mass of electron, m = 9.1 × 10¯³¹ kg

charge on electron, q = 1.6 × 10^-19 C

acceleration due to gravity, g = 9.8 m/s²

To find : The intensity of electric field required to balance the weight of an electron.

solution : at equilibrium,

electrostatic force = weight of electron

⇒ qE = mg

⇒E = mg/q

⇒E = (9.1 × 10¯³¹ kg × 9.8m/s²)/(1.6 × 10^-19 C)

⇒E = (9.1 × 9.8/1.6) × 10¯¹² N/C

⇒E = 55.7375 × 10¯¹² N/C

⇒E = 5.57375 ≈ 5.6 × 10¯¹² N/C

Therefore the intensity of electric field is 5.6 × 10¯¹² N/C (approx).