Author Question: Define efficiency for an engine. Is it possible for an engine to have an efficiency equal to one? ... (Read 117 times)

lindiwe · **on:** Jul 29, 2018

Define efficiency for an engine. Is it possible for an engine to have an efficiency equal to one?

What will be an ideal response?

Question 2

The intensity level of a power mower at a distance of 1.0 m is 100 dB. You wake up one morning to find that four of your neighbors are mowing their lawn 20 m from your open bedroom window. What is the intensity level in your bedroom?

A)

80 dB

B)

104 dB

C)

400 dB

D)

50 dB

E)

40 dB

xoxo123 · **Reply #1 on:** Jul 29, 2018

Answer to Question 1

Efficiency is defined as the ratio of the useful power output to the power input. The efficiency is always less than one because no engine can create energy, and in fact, cannot even transform energy from one form to another without some going to friction, thermal energy, and other non useful forms of energy.

Answer to Question 2

A