JAMB - Physics (2001 - No. 20)
A working electric motor takes a current of 1.5 A when the p.d across it is 250V. If its efficiency is 80%, the power output is
300.0W
469.0W
133.0W
4.8W
توضیح
Efficiency = \(\frac{\text{power output}}{\text{power Input}}\)
=> \(\frac{80}{100} = \frac{\text{power output}}{1.5\times 250}\)
i.e power output = \(\frac{1.5\times250\times80}{100}\) = 300W