1. One electronvolt is equal to A. 1.6 10 19 C. B. 1.6 10 19 J. C. 1.6 10 19 V. D. 1.6 10 19 W. 2. A battery of internal resistance 2 Ω is connected to an external resistance of 10 Ω. The current is 0.5 A. What is the emf of the battery? A. 1.0 V B. 5.0 V C. 6.0 V D. 24.0 V IB Questionbank Physics 1
3. In the circuit below, which of the following will cause the greatest increase in the reading of the voltmeter? A. An increase in temperature B. An increase in light intensity C. A decrease in temperature D. A decrease in light intensity 4. This question is about electric circuits. (a) Define (i) electromotive force (emf ) of a battery. (1) IB Questionbank Physics 2
(ii) electrical resistance of a conductor. (1) (b) A battery of emf ε and negligible internal resistance is connected in series to two resistors. The current in the circuit is I. (i) State an equation giving the total power delivered by the battery. (1) (ii) The potential difference across resistor R 1 is V 1 and that across resistor R 2 is V 2. Using the law of the conservation of energy, deduce the equation below. ε = V 1 + V 2 IB Questionbank Physics 3
(c) The graph shows the I-V characteristics of two conductors, X and Y. On the axes below, sketch graphs to show the variation with potential difference V of the resistance of conductor X (label this graph X) and conductor Y (label this graph Y). You do not need to put any numbers on the vertical axis. (3) IB Questionbank Physics 4
(d) The conductors in (c) are connected in series to a battery of emf ε and negligible internal resistance. The power dissipated in each of the two resistors is the same. Using the graph given in (c), (i) determine the emf of the battery. (ii) calculate the total power dissipated in the circuit. (Total 12 marks) IB Questionbank Physics 5
5. A light-dependent resistor (LDR) and a fixed resistor are connected in the potential divider circuit shown below. The voltmeter reads 3.0 V. Which of the following changes would cause the reading on the voltmeter to increase? A. Swapping the positions of the LDR and the fixed resistor B. Increasing the resistance of the fixed resistor C. Increasing the amount of light shining on the LDR D. Decreasing the amount of light shining on the LDR 6. This question is about electric circuits. (a) Define (i) electromotive force (emf ) of a battery. (1) (ii) electrical resistance of a conductor. (1) IB Questionbank Physics 6
(b) A battery of emf ε and negligible internal resistance is connected in series to two resistors. The current in the circuit is I. (i) State an equation giving the total power delivered by the battery. (1) (ii) The potential difference across resistor R 1 is V 1 and that across resistor R 2 is V 2. Using the law of the conservation of energy, deduce the equation below. ε = V 1 + V 2 IB Questionbank Physics 7
(c) The graph shows the I-V characteristics of two conductors, X and Y. On the axes below, sketch graphs to show the variation with potential difference V of the resistance of conductor X (label this graph X) and conductor Y (label this graph Y). You do not need to put any numbers on the vertical axis. (3) IB Questionbank Physics 8
(d) The conductors in (c) are connected in series to a battery of emf ε and negligible internal resistance. The power dissipated in each of the two resistors is the same. Using the graph given in (c), (i) determine the emf of the battery. (ii) calculate the total power dissipated in the circuit. (Total 12 marks) IB Questionbank Physics 9
7. The graph shows the I V characteristics of two resistors. When resistors X and Y are connected in series, the current in the resistors is 2.0 A. What is the resistance of the series combination of X and Y? A. 7.0 Ω B. 1.3 Ω C. 1.1 Ω D. 0.14 Ω 8. This question is about electrical resistance. (a) A resistor of resistance 1.5 Ω is made from copper wire of radius 0.18 mm. The resistivity of copper is 1.7 10 8 Ω m. Determine the length of copper wire used to make the resistor............. IB Questionbank Physics 10
(b) The manufacturer of the resistor in (a) guarantees that the resistance is within 10 % of 1.5 Ω, provided that the power dissipation in the resistor does not exceed 1.0 W. (i) Suggest why the resistance of the resistor might be greater than 1.65 Ω if the power dissipation in the resistor is greater than 1.0 W. (ii) Show that, for a power dissipation of 1.0 W, the current in a resistor of resistance 1.5 Ω is 0.82 A. (1) IB Questionbank Physics 11
(iii) The 1.5 Ω resistor is connected in series with a variable resistor and battery of emf 6.0 V and internal resistance 1.8 Ω. Estimate the resistance R of the variable resistor that will limit the current to 0.82 A. (3) (Total 8 marks) IB Questionbank Physics 12
9. Two resistors, of resistance R 1 and R 2, are connected in series with a cell of emf ε and negligible internal resistance. Which expression gives the potential difference across the resistor of resistance R 1? A. R1 ε R 1 + R 2 B. R1 + R2 ε R1 C. R2 ε R 1 + R 2 R1 + R2 D. ε R2 IB Questionbank Physics 13
10. Two resistors, made of the same material, are connected in series to a battery. The length of resistor X is twice that of resistor Y, and X has twice the cross-sectional area of Y. resistance of X Which of the following gives? resistance of Y A. B. 1 4 1 2 C. 1 D. 4 11. Three identical resistors are connected to a battery as shown. Which of the following is a correct statement? A. The current through X is greater than that through Z. B. The potential difference across Z is greater than that across Y. C. The potential difference across resistor X and Y together is the same as that across Z. D. The current through Z is less than the total current through X and Y. IB Questionbank Physics 14
12. (a) Draw the complete diagram of the circuit that uses a potential divider, ammeter, voltmeter and cell to measure the current-voltage characteristics for component X. (3) IB Questionbank Physics 15
(b) The graph shows the current-voltage characteristics for the component X. Component X is now connected across the terminals of a cell of emf 2.0 V and negligible internal resistance. Use the graph to show that the resistance of X is 0.83 Ω............. (c) A resistor of constant resistance 1.0 Ω is connected in series with the cell in (b) and with X. Use the graph to deduce that the current in the circuit is 1.3 A................ (3) (Total 8 marks) IB Questionbank Physics 16
13. The tungsten filament of a lamp has a cross-sectional area A and length L. For a potential difference V across the filament, the current in the filament is I. The resistivity of the tungsten equals V A A.. I L I L B.. V A V L C.. I A D. I A V L 14. Which of the following is a correct unit of electromotive force (emf)? A. A Ω 1 B. Ω A 1 C. C J 1 D. J C 1 15. Which of the following correctly gives the resistance of an ideal ammeter and resistance of an ideal voltmeter? Ammeter Voltmeter A. infinite infinite B. zero zero C. zero infinite D. infinite zero IB Questionbank Physics 17