Back to Electrostatics & CapacitanceTwo large circular discs separated by a distance of 0.01 m are connected to a battery via a switch as
shown in the figure. Charged oil drops of density 900 kg m
−3
are released through a tiny hole at the
center of the top disc. Once some oil drops achieve terminal velocity, the switch is closed to apply a
voltage of 200 V across the discs. As a result, an oil drop of radius 8 \times 10
−7
m stops moving
vertically and floats between the discs. The number of electrons present in this oil drop is ________.
(neglect the buoyancy force, take acceleration due to gravity = 10 ms
−2
and charge on an electron
(e) = 1.6 \times 10
–19
C)
Class 12 • Physics • Chapter-1
Electrostatics & Capacitance
Question 852 of 858
852HardInteger TypeJEE Advanced2020
Two large circular discs separated by a distance of 0.01 m are connected to a battery via a switch as
shown in the figure. Charged oil drops of density 900 kg m
−3
are released through a tiny hole at the
center of the top disc. Once some oil drops achieve terminal velocity, the switch is closed to apply a
voltage of 200 V across the discs. As a result, an oil drop of radius 8 \times 10
−7
m stops moving
vertically and floats between the discs. The number of electrons present in this oil drop is ________.
(neglect the buoyancy force, take acceleration due to gravity = 10 ms
−2
and charge on an electron
(e) = 1.6 \times 10
–19
C)
Integer / Numeric Answer Type
Enter your answer as a number (integer or decimal).