Skip to content

Course home

Sign up

13.2 Transformers and the National Grid

EasyMediumHard
1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556
Question 37
H

A step-down transformer at a local substation supplies a street of houses.

The potential difference across the primary coil is 11 000 V11\,000\ \text{V}11000 V. The potential difference across the secondary coil is 230 V.

The current in the secondary coil is 550 A.

a.

The transformer is 100% efficient.

Calculate the current in the primary coil.

Use the equation

VP×IP=VS×ISV_P \times I_P = V_S \times I_SVP​×IP​=VS​×IS​

[3]
b.

The primary coil has 4400 turns.

Calculate the number of turns on the secondary coil.

Use the equation

VPVS=NPNS\displaystyle \frac{V_P}{V_S} = \frac{N_P}{N_S}VS​VP​​=NS​NP​​

[3]
c.

Explain why step-down transformers are placed close to the homes they supply.

[2]
Markscheme

13.2 Transformers and the National Grid Questions

  1. GCSE
  2. /Physics
  3. /13.2 Transformers and the National Grid

108 exam-style questions on Edexcel GCSE Physics 13.2 Transformers and the National Grid, covering 13.2.1 Transformers and induction, 13.2.2 The transformer turns-ratio equation, 13.2.3 The National Grid, 13.2.4 The transformer power equation, and 13.2.5 Advantages of high-voltage transmission. Each one has a worked solution and a mark scheme showing where the marks go.

Question bank