Which of the following law is used in the Millikan's method for the determination of charge
Ampere's law
Stoke's law
Fleming's left hand rule
Fleming's right hand rule
An oxide coated filament is useful in vacuum tubes because essentially
A metal plate gets heated, when cathode rays strike against, it due to
Energy of electrons can be increased by allowing them
In the Millikan's experiment, the distance between two horizontal plates is $2.5 \,\,cm$ and the potential difference applied is $250\,\, V$ . The electric field between the plates will be ....... $V/m$
The current conduction in a discharged tube is due to