Physics · May / June 2021 · Paper 41 · Question 8
0625
As printed in the paper
The question as text
A student sets up a circuit that includes a 12 V battery, an 800 Ω resistor, a voltmeter and a thermistor. Fig. 8.1 is an incomplete circuit diagram because the symbol for the thermistor is missing. P Q 800 Ω 12 V V Fig. 8.1 The thermistor is connected between terminals P and Q.
Read automatically from the paper; the printed page above is exact.
Show the answer and mark scheme
8(a)[1]
and between P and Q
8(b)[1]
1.5 V c.a.o.
8(c)(i)[3]
1600 Ω
(V800 Ω =) 4.0 (V)
(I =) V / R in any form or 4.0 / 800 or 0.0050 (A) or (R =) V / I or 8.0 / 0.0050
OR
1600 Ω
(V800 Ω =) 4.0 (V)
(RTh =) R800 Ω × VTh / V800 Ω in any form or (RTh =) 800 × 8.0 / 4.0 in any form
OR
1600 Ω
12
8.0
RTh
or
or
800+RTh
RTh
800+RTh
12
8.0
in any form800+RTh
RTh
8(c)(ii)[3]
larger proportion of the e.m.f. (across thermistor) or smaller voltage across 800 Ω
temperature (of thermistor) is smaller / has decreased
resistance of thermistor / circuit is large(r)
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