J.J. Thomson discovered electron in
1892
1893
1864
1895
Electric current in metal wires is due to the flow of
protons
neutrons
electrons
orbits
The velocity of electro magnetic waves.
3 lakh kilometers per second
5 lakh kilometers per second
4 lakh kilometers per second
1 lakh kilometers per second
Cinematography works on the principle of
Electro magnetic indection
Persistence of vision
Chromatography
Photo electric effect
A radio set receives electro magnetic waves and converts them in to sound waves back with the help of
antenna
receiver
speaker
tuner
The wireless system was invented by
Marconi
Graham Bell
Edison
Newton
Radio works with the help of
electro magnetic waves
sound waves
light waves
magnetic waves
Who invented telephone?
J.J.Thomson
Robert Wolof
Einstein
Which among the following is used for recording in magnetic recording system?
Plastic tape
Disc
Diaphragm
Pencil
The atomic number of an atom is equal to its
number of nucleus
number of neutrons
number of electrons
atomic mass