Question

4. If an electric motor 'A' delivers output of 700 watts and takes input power of 1000 watts and another motor 'B' delivers an output of 600 watts and takes an input power of 2000 watts, then which motor is more efficient?
A. Motor A
B. Motor B
C. Cannot be determined
D. Both A and B are equally efficient

Answer 1

Answer:

moter A

Explanation:

efficiency = output/ input

by using this

A has more efficiency than B.

Answer 2

Answer:

A. Motor A. Efficiency of motor A is $70\%$.

Explanation:

Efficiency can be calculated by dividing the output of a machine from the input supplied.

1) Efficiency of motor 'A':

Efficiency, $\eta=$ (Output/Input) $\times100$

$\eta=\frac{700}{1000} \times100\\\eta=70\%$

2) Efficiency of motor 'B':

Efficiency, $\eta=$ (Output/Input) $\times100$

$\eta=\frac{600}{2000} \times100\\\eta=30\%$

The efficiency of motor A is $70\%$ and the efficiency of motor B is $30\%$.

Therefore, Motor A is more efficient.