When a toothbrush is charging, p.d. across the primary coil is 230 V, p.d. across the secondary coil is 7.2 V. The primary coil in the charging base has 575 turns of wire on its coil. Find the number of turns on the secondary coil inside the toothbrush.
This question is on transformers. This is clear because there is a primary and secondary coil and a different voltage between the 2 coils. Transformers induce a changing voltage in a coil. The known equation for finding the number of coils is: primary voltage / secondary voltage = turns on primary / turns on secondary.
Therefore numbers can be subbed in: 230/7.2=575/turns on secondary. This is rearranged to get 18.
JT
Related Physics GCSE answers
All answers ▸If a box full of feathers and a box full of bricks were to be dropped at the same time and from the same height, which one would hit the ground first?
A person swims from a depth of 0.5m to 1.7m below the surface of the sea. Denisty Sea Water = 1030 kg/m^3. g=Gravitational Field Strength = 9.8 N/kg. Calculate the change in pressure on the swimmer and give the unit.
a) Give an example of an alpha radiation source used in homes b) Why is it safe to use a source of alpha radiation in the house
What are the changes in energy that an object experiences when it is launched vertically at a given velocity into the air and falls back to the ground? This question ignores air resistance.