National 5 Physics. Electricity and Energy. Revision for Section 1 Test

Transcription

1 National 5 Physics Electricity and Energy Revision for Section 1 Test Conservation of Energy Electrical Charge Carriers and Electric Fields Potential Difference Ohm s Law Practical Electrical Circuits

2 Conservation of Energy Multiple Choice Questions Q1. ball of mass 0 50 kg is released from a height of 1 00 m and falls towards the floor. 1 00m 0 25m floor Which row in the table shows the gravitational potential energy and the kinetic energy of the ball when it is at a height of 0 25 m from the floor? Gravitational potential energy (J) Kinetic energy (J) B C D E Q2. car driving at 30ms -1 on a level road. It brakes until it is stationary. Which row gives the energy change of the car. Energy Change Kinetic to Kinetic B Potential to sound C Friction to heat D Kinetic to heat E Kinetic to friction 1 P a g e

3 Q3. man of mass 80kg dives from a diving board which is 10m above water. Neglecting air friction the kinetic energy of the diver immediately before he hits the water is B C D E 14J 800J 1200J 3900J 7800J Q4. ball is released from rest and allowed to roll down a curved track as shown. 0 20m start 0 80m The mass of the ball is 0.50kg. The maximum height reached on the opposite side of the track is 0.20m lower that the height of the starting point. The amount of energy lost is 0.080J B 0.01J C 0.98J D 2.9J E 3.9J track 2 P a g e

4 Conservation of Energy Extended Response Questions Q1. ski lift with a gondola of mass 2000kg travels to a height of 540m from the base station to a station at the top of the mountain. base station a. Calculate the gain in gravitational potential energy of the gondola. (3) b. During the journey, the kinetic energy of the gondola is J. Calculate the speed of the gondola. (3) Q2. child sledges down a hill from point to point B. The sledge and child have a combined mass of 40 kg. a. Calculate the gravitational potential energy of the child and sledge at point. (3) b. Find the kinetic energy of the child and sledge at point B. (1) c. Calculate the speed of the child at point B. (3) 3 P a g e

5 Electrical Charge Carriers and Electric Fields Multiple Choice Questions Q1. uniform electric field exists between plates Q and R. The diagram shows the path taken by a particle as it passes through the field. Which row in the table identifies the charge on the particle, the charge on plate Q and the charge on plate R? P Q R Charge on particle Charge on plate Q Charge on plate R negative positive negative B negative negative positive C no charge negative positive D no charge positive negative E positive positive negative Q2. The current in an 8 Ω resistor is 2. The charge passing through the resistor in 10 s is 4 C B 5 C C 16 C D 20 C E 80 C. 4 P a g e

6 Q3. The diagram shows the model of an atom. Which row in the table correctly describes particle and the particles in the nucleus. Particle Particles in the nucleus Electron Protons and electrons B Proton Protons and neutrons C Neutron Electrons and neutrons D Electron Electrons and Protons E Electron Protons and neutrons Nucleus Q4. Which of the following statements is/are correct? I II III B C D E In an a.c. circuit the direction of the current changes regularly. In a d.c. circuit positive charges flow in one direction only. In an a.c. circuit the size of the current varies with time. I only II only I and II only I and III only I, II and III Q5. n ampere is one B C D E volt per joule joule per second joule per coulomb coulomb per second ohm per volt. Q6. The charge passing a point in a conductor when a current of 4m flows for 1000s is 0.25C B 0.4C C 4.0C D 250C E 4000C 5 P a g e

7 Electrical Charge Carriers and Electric Fields Extended Response Questions Q1. Electrical storms occur throughout the world. During one lightning strike 24C of charge is transferred to the ground in s. a. Calculate the average current during the lightning strike. (3) b. The charge on an electron is C. Determine the number of electrons transferred during the lightning strike. (1) c. Many tall buildings have a thick strip of metal attached to the side of the building. This strip is used to protect the building from damage during electrical storms. Explain how this strip protects the building from damage. (2) Q2. Inside a storm cloud water droplets move around and collide with each other. water droplets Larger droplet The motion of water droplets in the cloud causes flashes of lightning. One lightning flash transfers 1650C of charge in 0 15s. Calculate the electric current produced by this flash. (3) Q3. Explain the difference be direct current (d.c.) and alternating current in terms of the movement of charges in a conductor. (2) 6 P a g e

8 Potential Difference Capacity Multiple Choice Questions Q1. Which of the following statements is/are correct? I II III B C D E The voltage of a battery is the number of joules of energy it gives to each coulomb of charge. battery only has a voltage when it is connected in a complete circuit. Electrons are free to move within an insulator. I only II only III only II and III only I, II and III Q2. The voltage of an electrical supply is a measure of the B C D E resistance of the circuit speed of the charges in the circuit power developed in the circuit energy given to the charges in the circuit current in the circuit. Q3. 1 volt is equivalent to 1 ampere per watt B 1 coulomb per second C 1 joule per coulomb D 1 joule per second E 1 watt per second. 7 P a g e

9 Ohm s Law Multiple Choice Questions Q1. In which circuit below would the meter readings allow the resistance of R2 to be calculated? B C D E 8 P a g e

10 Q2. Two resistors are connected in series with a 12 volt supply. The current in the 2Ω resistor is 2. Which row of the table gives the current in the 4Ω resistor and the voltage across the 4Ω resistor. Current in amperes Voltage in volts 1 4 B 1 12 C 2 8 D 2 12 E 4 8 Q3. You are given three 3.0Ω resistors and a 6.0V power supply and asked to build a circuit with a minimum current and another with a maximum current. Which row of the table give the minimum and maximum currents obtained with the equipment given. Minimum Current () Maximum Current () B C D E P a g e

11 Ohm s Law Extended Response Questions Q1. student investigates the resistance of a resistor using the circuit shown. a. Complete the circuit diagram to show where a voltmeter must be connected to measure the voltage across resistor R. (1) variable resistor R b. Describe how the student obtains a range of values of voltage and current. (1) c. The results of the student s investigation are shown. Use all these results to determine the resistance of resistor R. (4) Voltage across resistor R (V) Current in resistor R () d. The student now replaces resistor R with a filament lamp and repeats the investigation. sketch graph of the student s results is shown. State a conclusion that can be made about the resistance of the filament lamp. (1) voltage across Lamp(V) 0 current in lamp () 10 P a g e

12 Q2. resistor is labelled: 10 Ω ± 10%, 3 W. This means that the resistance value could actually be between 9 Ω and 11 Ω. a. student decides to check the value of the resistance. Draw a circuit diagram, including a 6 V battery, a voltmeter and an ammeter, for a circuit that could be used to determine the resistance. (3) b. Readings from the circuit give the voltage across the resistor as 5 7 V and the current in the resistor as Use these values to calculate the resistance. (3) c. During this experiment, the resistor becomes very hot and gives off smoke. The student states that two of these resistors would not have overheated if they were connected together in parallel with the battery. Is the student correct? Explain your answer. (2) Q3. student sets up the following circuit. a. Calculate the current in the 8.0Ω resistor. (4) b. Calculate the voltage across the 8.0Ω resistor. (3) c. The 24Ω resistor is replaced by one of greater resistance. How will this affect the voltage across the 8.0Ω resistor? Explain your answer. (2) 11 P a g e

13 Practical Electrical Circuits Multiple Choice Questions Q1. circuit is set up as shown. ₁ ₂ ₄ ₃ ₅ The reading on ammeter 1 is 5 0. The reading on ammeter 2 is 2 0. The reading on ammeter 4 is 1 0. Which row in the table shows the reading on ammeters 3 and 5? Reading on ammeter 3 () Reading on ammeter 5 () B C D E P a g e

14 Q2. Two resistors are connected as shown. 8 0 Ω P 24Ω Q The total resistance between P and Q is 0 17 Ω B 3 0 Ω C 6 0 Ω D 16 Ω E 32 Ω. Q3. Two circuits are set up as shown. R meter X R meter Y meter Z Both circuits are used to determine the resistance of resistor R. Which row in the table identifies meter X, meter Y and meter Z? meter X meter Y meter Z ohmmeter voltmeter ammeter B ohmmeter ammeter voltmeter C voltmeter ammeter ohmmeter D ammeter voltmeter ohmmeter E voltmeter ohmmeter ammeter 13 P a g e

15 Q4. circuit is set up as shown. 4 0Ω X 4.0Ω Y 4 0Ω The resistance between X and Y is 1 3Ω B 4 5Ω C 6 0Ω D 8 0Ω E 12Ω. Q5. circuit is set up as shown The reading on the ammeter is 3 0. The reading on the voltmeter is 4 0 V. Which row in the table shows the current in resistor R2 and the voltage across resistor R2. Current in resistor R 2 () Voltage across resistor R 2 (V) B C D E P a g e

16 Q6. student suspects that ammeter 1 may be inaccurate. mmeter 2 is known to be accurate. Which of the following circuits should be used to compare the reading on 1 with 2? + 6V R1 1 R2 2 B + 6V 1 2 R1 R2 C 1 + 6V 2 R1 R2 D + 6V R1 1 R2 2 E 1 + 6V R1 R P a g e

17 Q7. student makes the following statements about electrical circuits. I The sum of the potential differences across components connected in series is equal to the supply voltage. II The sum of the currents in parallel branches is equal to the current drawn from the supply. III The potential difference across components connected in parallel is the same for each component. Which of the statements is/are correct? B C D E I only III only I and II only II and III only I, II and III Q8. Three resistors are connected as shown The total resistance between X and Y is 2Ω B 4Ω C 8Ω D 13Ω E 22Ω. 16 P a g e

18 Q9. circuit is set up as shown. The current from the supply is 6. The current in resistor R1 is 1.5. Which row in the table shows the potential difference across resistor R2 and the current through resistor R2? Potential difference across R2 (V) Current in R2 () B C D E P a g e

19 Practical Electrical Circuits Extended Response Questions Q1. The technician builds a test circuit containing a resistor and a motor, as shown in Circuit 1. a. State the voltage across the motor. (1) b. Calculate the combined resistance of the resistor and the motor. (3) c. The resistor and the motor are now connected in series, as shown in Circuit 2. State how this affects the speed of the motor compared to Circuit 1. Explain your answer. (2) 18 P a g e