DP Physics (last assessment 2024)

Question 20N.2.HL.TZ0.9b(ii)

Date	November 2020	Marks available	[Maximum mark: 1]	Reference code	20N.2.HL.TZ0.9b(ii)
Level	HL	Paper	2	Time zone	TZ0
Command term	Estimate	Question number	b(ii)	Adapted from	N/A

b(ii).

[Maximum mark: 1]

20N.2.HL.TZ0.9b(ii)

The diagram shows an alternating current generator with a rectangular coil rotating at a constant frequency in a uniform magnetic field.

The graph shows how the generator output voltage $V$ varies with time $t$ .

Electrical power produced by the generator is delivered to a consumer some distance away.

(b(ii))

The voltage output from the generator is stepped up before transmission to the consumer. Estimate the factor by which voltage has to be stepped up in order to reduce power loss in the transmission line by a factor of $2.5 \times 10^{2}$ .

[1]

Markscheme

«power loss proportional to $I^{2}$ hence the step-up factor is $\sqrt{2.5 \times 10^{2}} » 16$ ✓

Examiners report

This was well answered by many, but some candidates left the answer as a surd. The most common guess here involved the use of root 2.

Syllabus sections

Additional higher level (AHL)

Additional higher level (AHL) » Topic 11: Electromagnetic induction » 11.2 – Power generation and transmission

Additional higher level (AHL) » Topic 11: Electromagnetic induction

Question 20N.2.HL.TZ0.9b(ii)

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