Answer:
The efficiency of the engine is 25%.
Step-by-step explanation:
Given that,
Output energy = 4000 J
Input energy = 16000 J
The efficiency of the engine is equal to the output energy divided input energy.
Formula of the efficiency is defined as,
![\eta =(Output\ energy)/(Input\ energy)*100]()
![\eta=(4000)/(16000)*100](https://img.qammunity.org/2020/formulas/physics/middle-school/rezgabbqe4e21rmsgh3owwxeqtogtzj1jj.png)
![\eta=0.025*100](https://img.qammunity.org/2020/formulas/physics/middle-school/7aoi2wgqgffw4le9qamp6avd5544wjp6pt.png)
![\eta=25\%](https://img.qammunity.org/2020/formulas/physics/middle-school/ybolv1js7gj0yaaxws9kj14lstwh0hrn6o.png)
Hence, The efficiency of the engine is 25%.