P15.8 Transformers in action

Question 1

What are the characteristics of a step up transformer?

Answer 1

Has more turns on its secondary coil than in its primary coil

Question 2

What are the characteristics of a step down transformer?

Answer 2

Has fewer turns in its secondary coil that in its primary coil

Question 3

What is the equation to find the number of turns/ p.d?

Answer 3

Vp / Vs = Np/Ns

Primary coil voltage / secondary = number turns primary/ secondary coil

Question 4

What is the equation if a transformer is 100% efficient?

Answer 4

Vp x Ip = Vs x Is

Question 5

Why is a step up transformer used when supplying p.d to the national grid?

Answer 5

Heating effect of a resistor or a wire is proportional to the square of the current

Increasing p.d - current through grid cables is reduced

because current needed to transfer the same amount of power is smaller

So heating effect is smaller and less power is wasted