Lesson 9 efficiency Flashcards
1
Q
what is the equation for efficiency
A
η=useful power output ÷ total power input
2
Q
what does effeciency tell us
A
what fraction of the energy we put into an appliance, is transferred to useful forms of energy
3
Q
in a pan, how can we reduce thermal energy passing into the air
(example)
A
pan with a wider base and a lid
4
Q
what is another issue with using a pan to heat water
(example)
A
a lot of the thermal energy is used to heat the base of the pan itself
5
Q
how can we overcome the thermal energy being used to heat the base of the pan itself
(example)
A
by placing a heating element inside the water
6
Q
plastic conducts heat less well than metal meaning what
A
the plastic has a lower thermal conductivity
