An engineering company has invented pavement tiles that generate electricity as people walk on them.
Use the Physics Equations Sheet to answer questions 03.1 and 03.2.
i- What equation links current (I), potential difference (V) and power (P)?
[1 marks]
SOLUTION
The correct formula is P=VI
When a person walks on a tile, a potential difference of 40 V is induced across the tile.
The power output of the tile is 4.4 W.
ii- Calculate the current in the tile.
[3 marks]
SOLUTION
Use the Physics Equations Sheet to answer questions iii and iv.
What equation links efficiency, total power input and useful power output?
[1 mark]
SOLUTION
The tiles are used to power LED lights in the pavement.
An LED light has a total power input of 4.0 W.
The efficiency of the LED light is 0.85
Calculate the useful power output of the LED light.
[3 marks]
SOLUTION
