JAMB - Physics (1998 - No. 40)
A transformer which can produce 8V from a 240v a.c. supply, has an efficiency of 80%. If the current in the secondary coil is 15A, calculate the current in the primary coil.
0.625A
1.600A
2.500A
6.250A
Vysvětlení
Efficiency = \(\frac{I_sV_s}{I_pV_p}\) x 100