ElectrostaticsHard
Question
An oil drop has a charge - 9.6 × 10-19 C and mass 1.6 × 10-15 gm. When allowed to fall, due to air resistance force it attains a constant velocity. Then if a uniform electric field is to be applied vertically to make the oil drop ascend up with the same constant speed, which of the following are correct. (g = 10 ms-2) (Assume that the magnitude of resistance force is same in both the cases)
Options
A.The electric field is directed upward
B.The electric field is directed downward
C.The intensity of electric field is 1/3 × 102 N C-1
D.The intensity of electric field is 1/6 × 105 N C-1
Solution
(initially) ∴ mg = fair 
(finelly ) ∴ QE = mg + fair = 2mg∴ charge is −ve, so electric field ′E′ is directed downwards.
& QE = 2 mg
∴ E =
NC-1Create a free account to view solution
View Solution FreeMore Electrostatics Questions
Identify the correct statements:A. Electrostatic field lines form closed loops.B. The electric field lines point radiall...A solid conducting sphere having a charge Q is surrounded by an uncharged concetric conducting hpllow spherical shell. L...The particle of mass m and charge q will touch the infinitely large plate of uniform charge density σ if its veloc...Which statement is true :(i) A ring of radius R carries a uniformly distributed charge +Q. A point charge −−...The electric potential varies in space according to the relation V = 3x + 4y. A particle of mass 0.1 kg starts from rest...