Answer: 
Energy is directly proportional to the frequency.
The energy of a photon is given by:
Where, E is the energy and 
is the frequency.
Frequency of the radio wave is given:
Multiply the above two:
Energy,
Hence, the energy of each photon of radio wave having frequency is 
Answer:
F = 8840.7 N
Explanation:
The parameters given are:
Length L = 3 metres
Extension e = 3 × 3 = 9m
Force constant K = 982.3 Newton per metre
From Hook's law,
Provided the elastic limit is not extended, the extension is directly proportional to the force applied.
That is,
F = Ke
Substitute all the parameters into the formula
F = 982.3 × 9
F = 8840.7 N
Answer:
14cm
Explanation:
Mass per gram of the piece of wire;
2g of the wire is found in 1m
Since
100cm = 1m;
So;
100cm of the wire contains 2g of the wire
To provide 0.28g
Since;
2g of wire is made up of 100cm
0.28g of wire will be contained in 
= 14cm
14cm of the wire will contain 0.28g
Answer:
On a brushed style generator, the increase in AC voltage from the slip rings is fed to the automatic voltage regulator, converted to DC voltage and fed into the rotor.
Explanation:
In an AC electrical generator, in order to maintain a fixed output, the output voltage is taken from the slip rings to the brushes (some generators don't have brushes) and converted to DC voltage (since it is an AC generator) and fed back to the rotor.
The rotor winding rotate inside a stationary magnetic field known as stater which induces electrical current in the winding. These winding are connected to slip rings which transfers the current to the outside circuit.
