TRANSFORMERS AND NATIONAL GRIDS
3 marks · NormalThe table shows information about two types of transformers.
| Type of transformer | Number of primary turns | Number of secondary turns | Use in National Grid |
|---|---|---|---|
| X | 300 | 9000 | |
| Y | 4000 | 200 |
Complete the table by stating the use of each transformer in the National Grid: either 'step-up' or 'step-down'.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
Show answer
Must show: X: step-up, Y: step-down
Common mistakes: Confusing step-up and step-down based on turn numbers
Show mark scheme and worked solution
Marking points
B1 · 1 mark · Identifies X as step-up transformer.
B2 · 1 mark · Identifies Y as step-down transformer.
B3 · 1 mark · Accurate answers for both together (both correct for 3 marks).
Worked solution
| Type of transformer | Number of primary turns | Number of secondary turns | Use in National Grid |
|---|---|---|---|
| X | 300 | 9000 | step-up |
| Y | 4000 | 200 | step-down |