The document lists a series of letters and numbers. It then provides 3 short paragraphs about: 1) How alternating voltage can be stepped up or down with little power loss using transformers compared to direct voltage; 2) A calculation showing a step-up transformer with a turn ratio of 2 taking an input of 120V at 8.33A RMS to an output of 1000V; 3) Mentions overhead power lines are cheaper to install and maintain than underground lines but can be blown against buildings in windy conditions.
1 of 1
Downloaded 11 times
More Related Content
J2 Physics 2008 prelim solutions Alternating current
1. 1. C
2. A
3. C
4. D
5. C
6. A
7. A
8. D
9. B
10. B
11.
(a)(i)
Alternating voltage can be stepped up or down with little power loss whereas direct voltage cannot be stepped up or down easily.
(ii) Step-up transformer with turn ratio 2.
(iii) Assuming no power losses in the transformer,
120Ip = 1000
Ip = 8.33 A r.m.s.
(b)(i)
Cheaper to install and maintain.
(ii) Can be blown against buildings in windy conditions.
