(a)
For the correct answer:
7200
To find the secondary turns, we apply the transformer ratio formula: V s V p = N s N p . From the diagram, the primary voltage V p is 25 kV and the secondary voltage V s is 360 kV. Substituting the known values (N p =500) into the rearranged formula N s =N p ×( V p V s ) gives 500×( 25 360 ), resulting in 7200 turns on the secondary coil.
(b)
For the correct answer:
Reduced power loss AND improved efficiency
Transmitting electricity at high voltages significantly reduces the current flowing through the cables for a given power level (P=IV). Since power loss in transmission lines is proportional to the square of the current (P=I 2 R), a lower current minimizes heat dissipation in the wires. This makes the overall distribution system much more efficient and cost-effective over long distances.
