Physics · Oct / Nov 2020 · Paper 42 · Question 10
0625
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The question as text
Fig. 10.1 shows an incomplete electrical circuit. 2.0 Ω 6.0 Ω 4.0 Ω E C F D A B Fig. 10.1
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10(a)(i)[1]
recognisable ammeter in gap AB AND straight lines in CD AND EF
10(a)(ii)[2]
recognisable voltmeter across 4 Ω
correct voltmeter symbol used
10(a)(iii)[4]
V = IR in any form or (V =) IR words, symbols or numbers
(V2Ω = 2 × 2.5 =) 5 V
(I4Ω = 5 ÷ 4 =) 1.3 A
must be clear that I refers to 4 Ω
OR calculates Rp = 1.33 Ω OR 4 ÷ 3 Ω
(I6Ω = 2.5 + 1.3 =) 3.8 A
OR (I6Ω = 5 ÷ 1.33 =) 3.8 A
Alternative route for first 3 mps
I proportional to 1 ÷ R OR I2Ω × R2Ω = I4Ω × R4Ω
I4Ω = I2Ω ÷ 2
(I4Ω = I2Ω ÷ 2 = 2.5 ÷ 2 =) 1.3 A
Alternative route by potential divider
V = IR in any form or (V =) IR words, symbols or numbers
(V2Ω = 2 × 2.5 =) 5 V
VT = 7.33 × 5 ÷ 1.33 (= 27.51 V)
(I6Ω = 27.51 ÷ 7.33 =) 3.8 A
10(b)[2]
any sort of triangle symbol pointing to left in EF
a wire in CD
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