0QUESTION
Describe schematically the equipotential surfaces corresponding to
(i) a constant electric field in the Z-direction,
(ii) a field that uniformly increases in magnitude but remains in a constant (say Z) direction and
(iii) a single positive charge at the origin.
ANSWER
(i) As the constant electric field in the Z-direction, the equipotential surfaces are normal to the field, i.e. in XY-plane. The equipotential surfaces are equidistant from each other.
(ii) As, the electric field increases in the direction of Z-axis, the equipotential surface is normal to Z-axis, i.e. in XY-plane and they become closer and closer as the field increases.
(iii) As a single positive charge is placed at origin, the equipotential surfaces are concentric spheres with origin at centre.
QUESTION
(a) Explain any two factors which justify the need of modulating a low frequency signal.
(b) Write two advantages of frequency modulation over amplitude modulation
ANSWER
a) (i) Effective power radiated by an antenna.
(ii) To avoid mixing up of signals from different transmitters.
(b) (i) FM signals can be demodulated even if the signal strength is weak.
(ii) FM reception is quite immune to noise as compared to AM reception.
