4.2.4. Resistance
A subsection of Physics, 5054, through 4. Electricity and magnetism
Listing 10 of 149 questions
A 600 Ω resistor and a thermistor are connected in series with an ammeter and a 20 V d.c. (direct current) power supply. A voltmeter is in parallel with the resistor. is the circuit diagram. V A 600 1 thermistor 20 V d.c. power supply + _ The ammeter reads 0.025 A. Calculate the reading on the voltmeter, reading = the resistance of the thermistor. resistance = The temperature of the thermistor increases. State what, if anything, happens to the resistance of the thermistor, the ammeter reading and to the voltmeter reading. ammeter reading: voltmeter reading:
5054_w12_qp_21
THEORY
2012
Paper 2, Variant 1
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A student makes a 2.0 V battery by connecting two cells of electromotive force (e.m.f.) 2.0 V in parallel. The battery, an ammeter with different ranges and three different resistors are used to set up the circuit shown in . A 2.0 1 2.0 V 2.0 V 3.0 1 X Explain what is meant by electromotive force. State one advantage of using two cells in parallel rather than using a single 2.0 V cell. Resistor X and the 3.0 Ω resistor have a combined resistance that is equal to 2.0 Ω. Calculate the total resistance of the circuit, total resistance = the resistance of X. resistance of X = Determine the reading of the ammeter. reading = Suggest a suitable range for the ammeter. The current in the 2.0 Ω resistor is I2. The current in the 3.0 Ω resistor is I3. The current in X is IX. State the equation that relates I2, I3 and IX. State the potential difference (p.d.) across the 2.0 Ω resistor, p.d. = the 3.0 Ω resistor. p.d. = Question 11 continues on page 18. The student sets up a second circuit using a variable d.c. power supply, an ammeter and a 12 V metal filament lamp. The circuit is shown in Fig. 11. 2. A + d.c. power supply metal filament lamp – The d.c. power supply is set to 12 V and the ammeter reading is 1.5 A. The student changes the e.m.f. of the d.c. power supply to 6.0 V. The lamp dims and the ammeter reading changes. State and explain what happens to the resistance of the metal filament of the lamp. State whether the new ammeter reading is less than, equal to or greater than 0.75 A.
5054_w14_qp_21
THEORY
2014
Paper 2, Variant 1
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The circuit of includes an ammeter, a 6.0 Ω resistor, a length of metal resistance wire and three 1.5 V cells connected in parallel. 6.0 1 1.5 V 1.5 V 1.5 V metal resistance wire A P Q State one advantage of using cells in parallel rather than using a single cell, the potential difference (p.d.) between points P and Q in the circuit of . p.d. = The ammeter in reads 0.075 A. Calculate the resistance of the resistance wire. resistance = The temperature of the metal resistance wire increases. State and explain the effect of this temperature increase on the ammeter reading.
5054_w14_qp_22
THEORY
2014
Paper 2, Variant 2
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Questions Discovered
149