10 N acts on a charge in an electric field of strength 250 N.C What is the value of the charge?

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Leslie Murphy
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1 Year 11 Physics Electrical Energy in the Home Name: 1. Draw the electric field lines around a) a single positive charge b) between two opposite charged bodies c) two parallel plates A force of 5 10 N acts on a charge in an electric field of strength 250 N.C What is the value of the charge? 3. A proton is placed is placed in a uniform electric field of 1000 N.C -1. What is the force acting on the proton? 4. An electron is released from rest from the negative plate from a pair of parallel, oppositely charged plates. If the electric field strength between them is 500N.C -1 and the distance between them is 5 cm a) Determine the force exerted on the electron. b) What is the acceleration the electron experiences? c) Determine the velocity with which the electron strikes the positive plate A current of 5 amps flows in a wire. a) What charge flows past a point in the wire in l minute? b) How many electrons pass a given point in the wire in that point? 6. In what direction does conventional current flow? 7. A piece of wire of length 1 and cross-section A had a resistance of 10 ohms. What would be the resistance of a piece of wire of the same material if the length was 21 and the cross-section was 2A? 8. An experiment was carried out where the current through a tungsten filament globe was increased and the potential difference across the globe measured as the current changed. The results are shone in the table below. 1

2 I (A) V (V) a) Draw the circuit which would have been used for this experiment. b) Plot a graph of V vs I from the table c) What does the slope of this graph represent? d) Is the slope constant/ Explain any in the graph. e) Use the graph to find i) the P.D. across the globe when the current is 0.5 A. ii) the resistance of the globe at 0.5 A. 2

3 9. Consider the circuit below: 10, In the circuit below find the reading on the ammeter A when the switch is a) open b) closed If the ammeter reads 4 A fend the value of: a) the resistance R. b) P.D. across the parallel circuit c) the current through each resistor. 11. List three advantages that a parallel circuit would have over a series circuit in household wiring. 12. If electricity costs 15c per kilowatt-hour calculate i) the energy consumed ii) the cost of using: a) 2000W radiator for 6 hours b) a 100 W globe and a 1kW radiator for 3 hours. c) a 7200 W water heater for 15 minutes. 13. For the magnetic field shown draw the direction of the current a) b) c). X X X X X X X X.... X.... 3

4 14. Draw the magnetic lines of force around the coil shown below. 15. A circuit is shown below. If the current in the 18 ohm resistor is 0.50 A, what is a) the P.D. between A and G? b) the current in the 9.0 ohm resistor? c) the current in the 2.0 ohm resistor? d) the P.D. between G and B? e) The current in the 4.0 ohm resistor? f) the total resistance of the circuit? g) the total current the battery provides? Data: Mass of an electron = 9.91 X g Mass of a proton = 1.67 X kg Charge on an electron = -1.6 X Coulombs Charge on a proton = X Coulombs 4

5 Year 11 Physics Electrical Energy in the Home Name: 1. Draw the electric field lines around a) a single positive charge b) between two opposite charged bodies c) two parallel plates A force of 5 10 N acts on a charge in an electric field of strength 250 N.C What is the value of the charge? 6 F q = = = 2 10 C E A proton is placed is placed in a uniform electric field of 1000 N.C -1. What is the force acting on the proton? F = qe = = N(direction) 4. An electron is released from rest from the negative plate from a pair of parallel, oppositely charged plates. If the electric field strength between them is 500N.C -1 and the distance between them is 5 cm a) Determine the force exerted on the electron. F = qe = = 8 10 N b) What is the acceleration the electron experiences? F = ma F a = m = = m / s c) Determine the velocity with which the electron strikes the positive plate.??? 5. A current of 5 amps flows in a wire. a) What charge flows past a point in the wire in l minute? q = 5 60 = 300C b) How many electrons pass a given point in the wire in that point???? 6. In what direction does conventional current flow? Positive to Negative 7. A piece of wire of length 1 and cross-section A had a resistance of 10 ohms. What would be the resistance of a piece of wire of the same material if the length was 21 and the cross-section was 2A? -1 1

6 1 R = p a R = 10Ω 8. An experiment was carried out where the current through a tungsten filament globe was increased and the potential difference across the globe measured as the current changed. The results are shone in the table below. I (A) V (V) a) Draw the circuit which would have been used for this experiment. b) Plot a graph of V vs I from the table (Looks like y=sqr(x) graph) c) What does the slope of this graph represent? The resistance of the globe at different currents/voltages. d) Is the slope constant/ Explain any in the graph. No. It is not constant because the globe is not ohmic (ie. energy is also given off as light.) e) Use the graph to find i) the P.D. across the globe when the current is 0.5 A. 3.5V ii) the resistance of the globe at 0.5 A. V 3.5 R = = = 7Ω I Consider the circuit below: If the ammeter reads 4 A fend the value of: a) the resistance R.??? b) P.D. across the parallel circuit V = IR = 8V 10, In the circuit below find the reading on the ammeter A when the switch is a) open R = 5Ω V I = = R b) closed R = 4Ω I = V R 12 5 = 2.4A 12 = = 3A 4 2

7 c) the current through each resistor. I = 4A I I I 6Ω 5Ω 4Ω 2Ω = 1.6A = 2A = 0.4A 11. List three advantages that a parallel circuit would have over a series circuit in household wiring. If one wire breaks, the rest of the circuit still works. The components all receive the same voltage. It is easier to identify (and fix) the broken/faulty section. 12. If electricity costs 15c per kilowatt-hour calculate i) the energy consumed ii) the cost of using: a) 2000W radiator for 6 hours i) E = Pt = 43. 2MJ ii) $1.80 b) a 100 W globe and a 1kW radiator for 3 hours. i) E=10.8MJ ii) $0.495 c) a 7200 W water heater for 15 minutes. i) E=6.48MJ ii) $ For the magnetic field shown draw the direction of the current a) b) c). X X X X X X X X.... X Draw the magnetic lines of force around the coil shown below. 3

8 15. A circuit is shown below. If the current in the 18 ohm resistor is 0.50 A, what is a) the P.D. between A and G? V = = 9V b) the current in the 9.0 ohm resistor? V I = = 1A R c) the current in the 2.0 ohm resistor? I = 1. 5A d) the P.D. between G and B? V = = 3V e) The current in the 4.0 ohm resistor? f) the total resistance of the circuit? 2.6 Ω g) the total current the battery provides? V 12 I = = = 4. 5A R 2.6 Data: Mass of an electron = 9.91 X g Mass of a proton = 1.67 X kg Charge on an electron = -1.6 X Coulombs Charge on a proton = X Coulombs 4

Electricity Final Unit Final Assessment

Electricity Final Unit Final Assessment Name k = 1/ (4pe 0 ) = 9.0 10 9 N m 2 C -2 mass of an electron = 9.11 10-31 kg mass of a proton = 1.67 10-27 kg G = 6.67 10-11 N m 2 kg -2 C = 3 x10 8 m/s Show all