Home
/
Physics
/
An electric drill transfers 200 J of energy into a useful kinetic energy store. It wastefully transfers 92 J of energy to the thermal store of the drill and the surroundings . What is the efficiency of this drill? Give your answer as a percentage to 2 significant figures.

Question

An electric drill transfers 200 J of energy
into a useful kinetic energy store. It
wastefully transfers 92 J of energy to the
thermal store of the drill and the
surroundings . What is the efficiency of this
drill? Give your answer as a percentage to 2
significant figures.

An electric drill transfers 200 J of energy into a useful kinetic energy store. It wastefully transfers 92 J of energy to the thermal store of the drill and the surroundings . What is the efficiency of this drill? Give your answer as a percentage to 2 significant figures.

expert verifiedVerification of experts

Answer

4.6281 Voting
avatar
XerxesMaster · Tutor for 5 years

Answer

<p> 200 / 292 * 100 ≈ 68.49 ≈ 68</p>

Explain

<p> The efficiency of a device or system can be defined as the ratio of useful output energy (or power) to input energy (or power). It essentially gives us an idea of how well a system or device converts the energy (or power) it gets into the energy (or power) we want, without wasting any. Efficiency is usually expressed as a percentage. Mathematically, it can be calculated as <br />Efficiency (%) = (Useful output energy/Input energy) x 100.<br />In this particular question, we have been given 1. Useful output energy = 200J and 2. Input energy = Useful output energy + Wasteful energy = 200J + 92J = 292J. Now let's plug these values into the equation of efficiency and do the calculation.</p>
Click to rate:

Hot Questions

More x