NYGH Lower Sec Science Multiple Choice Questions on Electricity Answers

1 Sc!ence Name: …………………… ( ) Class: ……………… Date: …… / …… / …… Multiple-Choice Questions on Electricity – Answers 1. A student measures the potential difference across a device and the current in the device. Which calculation gives the resistance of the device? A current + potential difference B current  potential difference C potential difference  current D potential difference  current 2. The diagram shows three ammeters. Which ammeters show the same value of current? A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only 3. The diagram shows part of an electric circuit. What is the reading on the ammeter? A 6.0 A B 3.0 A C 1.5 A D 0.75 A

2 4. Two identical resistors are connected to a 15 V cell as shown in the circuit below. Which of the following correctly describes the readings on the ammeters A1 and A2 when switch K is closed? A A2 has the same reading as A1. B A2 has half the reading as A1. C A2 has double the reading of A1. D A1 has a zero reading while A2 has a non-zero reading. 5. The following diagrams show two lamps, a switch and a battery connected in a circuit. Which one of the circuits is not equivalent to the other three circuits? Answer = C A B C D

3 6. A voltmeter and an ammeter are used to measure the resistance of a resistor. Which diagram shows the voltmeter and the ammeter correctly connected? Answer = B 7. The diagram shows three identical resistors, three ammeters and a battery, connected in a circuit. What is the order of the magnitudes of the readings on the ammeters from smallest to largest? A ammeter 1 < ammeter 2 < ammeter 3 B ammeter 1 < ammeter 3 < ammeter 2 C ammeter 2 < ammeter 3 < ammeter 1 D ammeter 3 < ammeter 2 < ammeter 1 8. A lamp is connected across one cell, then across two cells. The potential difference (p.d.) across the lamp and the current in it are measured in each case. The results are shown. number of cells p.d. / V current / A 1 2.8 0.25 2 5.4 0.4 What is the change in the resistance of the lamp when the number of cells is increased from one to two? A It decreases by 0.015 . B It increases by 1.5 . C It increases by 2.3 . D It increases by 17 .

4 9. The diagram shows a cell connected to three resistors, R1, R2 and R3. A student connects an ammeter first in position 1, then in position 2, 3 and 4 in turn. In which position(s) does the ammeter show the current in R1? A 1, 2 and 4 B 1 and 2 only C 3 only D 4 only 10. A student sets up a circuit which she calls circuit 1. She records the value of the current I1, and calculates the resistance R1 of the circuit. She then connects an identical resistor in parallel with the original resistor. She calls this circuit 2. She records current I2 and calculates the total resistance R2 of this circuit. Which row correctly compares the two currents and the two resistances in the circuits? A I2 is greater than I1 and R2 is greater than R1. B I2 is greater than I1 and R2 is less than R1. C I2 is less than I1 and R2 is greater than R1. D I2 is less than I1 and R2 is less than R1.

5 11. The diagram shows a circuit including a lamp, an electric bell and three switches S1, S2 and S3. The lamp and bell are not faulty. The bell is ringing but the lamp is not lit. Which switches are closed? A S1 only B S1 and S2 only C S1 and S3 only D S1, S2 and S3 12. A student is designing a lighting circuit for a dolls’ house. She sets up two different circuits. Each circuit contains a 12 V power supply and three identical lamps. Each lamp is designed to operate at normal brightness when connected individually to a 12 V supply. Which statement is correct? A In circuit 1, each of the lamps is at normal brightness. B In circuit 1, if one lamp fails, the other lamps remain lit. C In circuit 2, if one lamp fails, the other lamps remain lit. D In circuit 2, the current from the power supply is less than in circuit 1.

6 13. A student uses the circuit shown to determine the resistance of two identical resistors. The voltmeter reading is 2.2 V and the ammeter reading is 0.25 A. What is the resistance of each resistor? A 0.275  B 0.55  C 4.4  D 8.8  14. In the circuit shown, A1 and A2 are ammeters. Switch S is closed. Which row is correct? resistance of whole circuit reading of A1 reading A2 A decreases same increases B decreases increases increases C increases same same D increases decreases decreases

7 15. The diagram shows a circuit. The wire between P and Q can be removed and replaced by a circuit component. Where should a voltmeter be connected to measure the potential difference (p.d.) across the lamp? A between P and Q in place of the wire B in parallel with R and S C in parallel with R and T D in parallel with S and T 16. The circuit shown contains five lamps J, K, L, M and N. All the lamps are glowing. One lamp is removed and two other lamps go out. Which lamp is removed? A lamp J B lamp K C lamp L D lamp M

8 17. The diagram shows part of a circuit containing three identical lamps. At which two points do the currents have the same value? A W and X B W and Z C X and Y D Y and Z 18. A student constructs four circuits, each containing a fuse. The fuse blows in one circuit and both lamps in the circuit go out. In which circuit does the fuse blow and both lamps go out? Answer = D

9 19. Study the circuit diagram given below. Which resistor has a potential difference of 3.6 V across it? A R1 B R2 C R3 D R4 20. Study the circuit diagram given below. Which combination of values for R1 and R2 will give an effective resistance of 1.6 ? A R1 = 2.0 , R2 = 4.0  B R1 = 2.0 , R2 = 8.0  C R1 = 4.0 , R2 = 4.0  D R1 = 4.0 , R2 = 8.0  21. Two resistors, with resistances R1 and R2, are connected in parallel. The resistance R1 is greater than the resistance R2. What is the resistance of the parallel combination? A Less than either R1 or R2. B Equal to R1. C Equal to R2. D The average of R1 and R2.

10 22. A battery is connected to two crocodile clips and a lamp. There is a gap between the crocodile clips. Four cylinders W, X, Y and Z are made of the same metal but have different dimensions. The cylinders are connected in turn, by their ends, between the crocodile clips. The diagrams of the cylinders are all drawn to the same scale. Which cylinder makes the lamp glow most brightly and which cylinder makes the lamp glow least brightly? most brightly least brightly A W Y B W Z C X Y D X Z 23. The diagram shows a 40  resistor and a 60  resistor connected in parallel. What is the total resistance between points P and Q? A Less than 40  B 50  C Between 60  and 100  D 100 