A24-volt source is required to furnish 48 watts to a parallel circuit consisting of four resistors of equal value. what is the voltage drop across each resistor?

The resistors are all in parallel across the source.

Therefore each resistor is connected, through wire, directly across the source.

Therefore the full 24 volts appears across each resistor ... even if their values are not equal.

r=rho l/a where a is the area, l is the length and rho is resistivity so the greater the area the lesser the resistance thats why the earth pin is thicker bcos current follow the shortest path, so less resistive .