To determine the efficiency of the machine, we use the formula for efficiency which is given by:
[tex]\[ \text{Efficiency} = \left( \frac{\text{Useful Power Output}}{\text{Power Input}} \right) \times 100 \][/tex]
Given:
- Power Input (Power Supplied) = [tex]\( 4000 \text{ W} \)[/tex]
- Useful Power Output (Power Useful) = [tex]\( 1900 \text{ W} \)[/tex]
Substituting the values into the formula:
[tex]\[ \text{Efficiency} = \left( \frac{1900 \text{ W}}{4000 \text{ W}} \right) \times 100 \][/tex]
[tex]\[ \text{Efficiency} = \left( \frac{1900}{4000} \right) \times 100 \][/tex]
[tex]\[ \text{Efficiency} = 0.475 \times 100 \][/tex]
[tex]\[ \text{Efficiency} = 47.5 \% \][/tex]
Therefore, the efficiency of the machine is [tex]\( 47.5 \% \)[/tex].
The correct answer is:
Efficiency [tex]$=47.5 \%$[/tex]
