Electromagnetic Waves — Physics STD 12 Science — Question

In LCR series AC circuit.

Audio signal cannot be transmitted because (a) The signal has more noise(b) The signal cannot be amplified for distance communication (c) The transmitting antenna length is very small to design(d) The transmitting antenna length is very large and impracticable

The net electric flux through a closed surface is:

The plates of a capacitor are charged to a potential difference of 320 volts and are then connected across a resistor. The potential difference across the capacitor decays exponentially with time. After 1 second  the potential difference between the plates of the capacitor is 240 volts, then after 2 and 3 seconds the potential difference between the plates will be(a) 200 and 180 V(b) 180 and 135 V(c) 160 and 80 V(d) 140 and 20 V

An amplitude modulated wave is modulated to 50%. What is the saving in power if carrier as well as one of the side bands are suppressed(a) 70%   (b) 65.4%(c) 94.4%(d) 25.5%

Those atoms which have the same atomic number but different mass number are called :

A horizontal circular loop carries a current that looks clockwise when viewed from above. It is replaced by an equivalent magnetic dipole consisting of a south pole S and a north pole N:

A concave mirror of focal length f, has formed the image of magnification m, the distance of the object from the mirror is :