The advantages of electronic mail are:
Fast communication
Cost free service
More efficient
All of these
In C.R.O grid is always connected with potential:
Negative
Positive
High positive
Zero positive
The instrument which is used to display the magnitude of changing electric current is called:
Evacuated tube
Cathode rays oscilloscope
Television tube
Picture tube
Simplest electrical circuits use:
One wire
Two wires
Four wires
Five wires
the waves have properties:
reflection
refraction
diffraction
all of these