Oxford Revise AQA GCSE Combined Science Foundation | Chapter P4 answers

P4: Electric circuits

Question

Answers

Extra information

Mark

AO / Specification reference

01.1

Lamp — A shaded circle with X mark on it. Connection lines extend to the left and right of the circle.

LED — A circle around a triangle pointing to the right with two diagonal arrows protruding from the top right of the circle. Connection lines extend to the left and right of the triangle.

Diode — A circle around a triangle pointing to the right. A vertical line in on the apex of the triangle. Connection lines extend to the left and right of the triangle.

Fuse — A horizontal line, part of which is enclosed within a rectangle. The line is visible inside the rectangle. Connection lines extend to the left and right of the rectangle.

one mark for two lines correct

two marks for three lines correct

three marks for four lines correct

3

AO1

6.2.1.1

01.2

A horizontal line, part of which is enclosed within a rectangle. The line is not visible inside the rectangle. Connection lines extend to the left and right of the rectangle.

1

AO1

6.2.1.1

01.3

an electric charge of two coulombs flows per second

1

AO1

6.2.1.2

02.1

one mark for ‘A’ in correct place

one mark for ‘V’ in correct place

one mark for resistor labelled correctly

one mark for variable resistor labelled correctly

4

AO1

4.2.1.1

02.2

A horizontal line, part of which is enclosed within a rectangle. The line is not visible inside the rectangle. Connection lines extend to the left and right of the rectangle.

1

AO1

4.2.1.2

02.3

A horizontal line, part of which is enclosed within a rectangle. The line is not visible inside the rectangle. A diagonal arrow pointing to the top right passes through the rectangle. Connection lines extend to the left and right of the rectangle.

1

AO1

02.4

the rate of flow of charge/charge flowing per second

1

AO1

02.5

\(
{\rm{resistance}} = \frac{\rm{potential\ difference}}{\rm{current}}
\)

or potential difference = current × resistance

\(
\rm{allow\ R\ }=\frac{\rm{V}}{\rm{I}}\ \rm{or\ V}\ =\ \rm{IR}
\)

1

AO1

4.2.1.3

02.6

\(
\rm{resistance} = \frac{\rm{potential\ difference}}{\rm{current}}
\) \(
\rm{R} =\frac{6}{0.3}
\)

= 20

accept 20 with no working for the two calculation marks

1

1

1

AO2

4.2.1.3

03.1

light dependent resistor/LDR

1

AO1

6.2.1.4

03.2

A circle around a slim rectangle. Two diagonal arrows pointing to the bottom right are on the top left of the circle. Connection lines extend to the left and right of the rectangle.

1

AO1

6.2.1.1

03.3

high

1

AO2

6.2.1.4

03.4

to record the measurements over a long period of time/to be able to store data on a computer/display the data on a computer

1

AO3

04.1

circuits A and C are parallel circuits

no mark if more than one box ticked

1

AO1

4.2.2

04.2

A, C

B, D

B, D

both letters needed for the mark in each case

letters can be in any order

1

1

1

AO2

4.2.2

04.3

no

the bulbs will be the same brightness

because they are in a series circuit/current is the same everywhere in a series circuit

1

1

1

AO2

4.2.2

05.1

a lamp

1

AO1

6.2.1.4

05.2

increases

1

AO2

6.2.1.4

05.3

hotter

more

harder

1

1

1

AO3

6.2.1.4

06.1

the diode only allows a current to flow in one direction

the diode has been connected so that the current cannot flow through it

1

1

AO3

6.2.1.4

06.2

potential difference = current × resistance

1

AO1

6.2.1.3

06.3

1.5 = 0.12 × resistance

\(
\rm{resistance} =\frac{1.5}{0.12}
\)

= 12.5 Ω

= 13 Ω

1

1

1

AO2

6.2.1.3

07.1

\(
\rm{average} =\frac{{{\rm{236\ }} + {\rm{\ 212\ }} + {\rm{\ 200\ }} + {\rm{\ 206}}}}{{\rm{4}}}
\)

= 213.5 (A)

1

AO2

6.1.3

07.2

number of solar cells/number of hours of daylight/clouds

1

AO3

6.1.3

07.3

\(
\rm{number\ of\ power\ stations\ }=\frac{{{\rm{1000}}}}{{{\rm{200}}}}
\)

= 5

1

1

AO2

6.1.3

07.4

Example answer:

both solar power stations and hydroelectric power stations use a lot of land

so destroy/change habitats of animals and plants

hydroelectric power stations involve flooding areas

neither produce carbon dioxide when in use so do not contribute to climate change.

4

AO3

6.1.3

08.1

independent = length

1

AO2

6.2.1.3

08.2

dependent = resistance

1

AO2

6.2.1.3

08.3

control – one from:

  • temperature
  • cross-sectional area/diameter
  • type of wire

1

AO2

6.2.1.3

08.4

one mark for length on x-axis and resistance on y-axis

one mark for straight line through the origin

2

AO2

6.2.1.3

08.5

a correct suggestion, e.g.,

the wire did not say the same temperature/there was a systematic error in one of the measuring instruments

AO3

6.2.1.3

09.1

A or ampere

1

AO1

6.2.1.4

09.2

the first measurement of current for a potential difference of 8 V/0.39 A in first column

1

AO3

6.2.1.4

09.3

\(
\frac{{{\rm{0}}{\rm{.12\ }} + {\rm{\ 0}}{\rm{.13\ }} + {\rm{\ 0}}{\rm{.14}}}}{{\rm{3}}} = 0.13
\)

1

AO2

6.2.1.4

09.4

one mark for correct points plotted: (0, 0), (2, 0.13), (10, 0.62), (12, 0.72)

one mark for straight line of best fit

2

AO2

AO3

6.2.1.4

09.5

line should have a steeper gradient than the original line

1

AO3

6.2.1.4

10.1

it stays the same

1

AO2

6.1.1.1

10.2

B

1

AO2

6.1.1.1

10.3

B

1

AO2

6.1.1.1

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