4.2. Electrical quantities
A subsection of Physics, 5054, through 4. Electricity and magnetism
Listing 10 of 319 questions
A student sets up the circuit shown in . A 6.0 V 2.8 Ω 3.6 Ω X The electromotive force (e.m.f.) of the battery is 6.0 V. The resistance of the variable resistor X is set to 1.8 Ω. Determine the total resistance of the circuit, resistance = the current measured by the ammeter. current = State what is meant by the potential difference (p.d.) across a component in a circuit. Add to the symbol for a component that is measuring the p.d. across the 2.8 Ω resistor. The resistance of X is increased. Explain why the p.d. across the 2.8 Ω resistor decreases.
5054_w18_qp_21
THEORY
2018
Paper 2, Variant 1
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is the circuit diagram of a circuit set up by a student. V P The student uses three cells, each of electromotive force (e.m.f.) 1.5 V. The cells are connected in series, as shown. State the name of component P. State what is meant by the electromotive force of a cell. The student expects the reading on the voltmeter to be 4.5 V. The actual reading is 0.2 V. Suggest two reasons why the voltmeter reading is much less than 4.5 V. In the space below, draw three cells connected in parallel. State one advantage of connecting cells in parallel.
5054_s12_qp_21
THEORY
2012
Paper 2, Variant 1
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Measurements are made of the current in a metal wire and the potential difference (p.d.) across it. shows a graph of the current against the p.d. for the wire. 0.1 0.2 0.3 0.4 current / A 0.5 p.d. / V State the relationship between the current and the p.d. for the metal wire. State how the graph shows that the temperature of the wire does not change in the experiment. Another wire of the same material has the same length as the original wire but has only half the cross-sectional area. 1. Compare the resistance of the new wire and the original wire. 2. On , draw the graph for the new wire. Three resistors are connected to a d.c. power supply, as shown in . The electromotive force (e.m.f.) of the power supply is 6.0 V. 6.0 V 24 Ω 20 Ω 80 Ω Calculate 1. the total resistance of the circuit, resistance = 2. the current supplied by the power supply, current = 3. the p.d. across the 20 Ω resistor. p.d. = The d.c. power supply is a battery that contains a number of cells. Each cell has an electromotive force (e.m.f.) of 1.5 V. 1. State what is meant by the electromotive force (e.m.f.) of a cell. 2. In the space below, draw a diagram to show how four of these cells are connected to make a battery of e.m.f. 6.0 V. Mark the positive terminal of the battery. 3. In another arrangement to produce a battery of e.m.f. 6.0 V, eight cells of e.m.f. 1.5 V are connected. In this arrangement, some cells are connected in series and some in parallel. In the space below, draw a diagram to show how the eight cells are connected to make the battery. State one advantage of using a battery made from cells in parallel rather than a single cell.
5054_s17_qp_22
THEORY
2017
Paper 2, Variant 2
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shows an electric circuit containing a filament lamp, a resistor R, a 12 V battery and five meters. A A A V V ammeter A3 resistor R 12 V ammeter A1 ammeter A2 voltmeter V1 voltmeter V2 The reading on ammeter A1 is 0.25 A. The reading on voltmeter V1 is 3.0 V. Determine the readings on the other meters. reading on ammeter A2 = A reading on ammeter A3 = A reading on voltmeter V2 = V Calculate the resistance of resistor R. resistance of resistor R = Ω The resistor obeys Ohm’s law. State Ohm’s law. shows the current–voltage graph for the filament lamp. 0.10 0.20 0.30 0.40 voltage / V current / A The battery in is replaced with a different battery which has a different e.m.f. (electromotive force). The voltage across the lamp increases to 6.0 V. Use data from the graph to determine the e.m.f. of the second battery. Show your working. e.m.f. = V
5054_s23_qp_22
THEORY
2023
Paper 2, Variant 2
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A 1500 Ω resistor is used on an electronic circuit board in a television. shows the bands on a resistor. band 1 band 3 band 2 digit or multiplier colour black brown red orange yellow green blue violet grey white The table of shows the colour code for the bands. State the colours of the bands on a 1500 Ω resistor. band 1 band 2 band 3 Determine the maximum value of resistance that can be shown with this three-band colour code. resistance = The 1500 Ω resistor on the electronic circuit board has a correct power rating of 0.25 W. State a disadvantage of using a different 1500 Ω resistor with a power rating that is 1. much less than 0.25 W, 2. much greater than 0.25 W. shows part of a circuit that includes a variable resistor R and a battery of e.m.f. 9.0 V. X R Y 9.0 V State one similarity and one difference between electromotive force (e.m.f.) and potential difference (p.d.). similarity: difference: A light-emitting diode (LED) is connected between points X and Y, so that it emits light. On , draw the symbol for the LED connected between points X and Y. The resistance of R is increased. State what happens to the p.d. across the LED and to the current in the LED. p.d.: current: The LED is marked “maximum current 25 mA when the p.d. is 1.7 V”. Calculate the minimum value of the resistance of R. resistance =
5054_s11_qp_21
THEORY
2011
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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Questions Discovered
319