Manipal MET2011PhysicsElectrostatics
In Millikan's oil drop experiment, a charged drop of mass 1.8 10⁻¹³ ~kg is stationary between its plates. The distance between its plates is 0.9 cm and potential difference is 2000 V . The number of electrons in the drop is
Options
- A500
- B50
- C5
- D10
Correct answer
B. 50
Step-by-step solution
Drop is stationary, i.e., weight of drop = electric force i.e., m g=q E or m g=q V d or m g=n e V d n= m g d e V aligned & = 1.8 10⁻¹³ 10 0.9 10⁻² 1.6 10⁻¹⁹ 2000 n & =50 aligned