Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 459 · 40 questions

Remember (Follow the loop): Closed circuit = complete loop = current flows; open circuit = a break = no current. Check every part: live cell, good bulb, switch ON, all wires joined, any gap bridged by a conductor. If even one check fails, the bulb does not glow.

1. 1.🔦 A circuit has a new cell, a good bulb and a switch that is ON. One wire has come loose from the cell. A gap in one wire is bridged by a glass marble. Does the bulb glow? (a) No (b) Yes
2. 2.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) none (b) only one (c) both of them (d) it does not matter
3. 3.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
4. 4.True or false: if the loop is complete, the circuit is open and no current flows. (a) False (b) True
5. 5.🔦 A circuit has a new cell, a good bulb and a switch that is ON. One wire has come loose from the cell. Does the bulb glow? (a) No (b) Yes
6. 6.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) False (b) True
7. 7.🔦 A circuit has a new cell, a good bulb and a switch that is OFF. All the wires are firmly joined. Does the bulb glow? (a) No (b) Yes
8. 8.Which of these means the circuit is closed? (a) a cell is taken out (b) a wire is cut (c) the switch is ON (d) a wire has come loose
9. 9.Which of these means the circuit is open? (a) a cell is taken out (b) the loop is complete (c) the switch is ON (d) all wires are joined
10. 10.🔁 What do we call a circuit with a break in it? (a) a series circuit (b) a closed circuit (c) a full circuit (d) an open circuit
11. 11.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
12. 12.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. Does the bulb glow? (a) No (b) Yes
13. 13.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
14. 14.Which of these means the circuit is open? (a) the bulb is unscrewed (b) the switch is ON (c) all wires are joined (d) the loop is complete
15. 15.True or false: if all wires are joined, the circuit is open and no current flows. (a) False (b) True
16. 16.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a woollen thread. Does the bulb glow? (a) No (b) Yes
17. 17.🔦 A circuit has a used-up (dead) cell, a good bulb and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a paper strip. Does the bulb glow? (a) Yes (b) No
18. 18.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
19. 19.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
20. 20.True or false: if the switch is OFF, the circuit is open and no current flows. (a) False (b) True
21. 21.Which of these means the circuit is open? (a) a wire is cut (b) the loop is complete (c) the switch is ON (d) all wires are joined
22. 22.True or false: if the switch is ON, the circuit is open and no current flows. (a) False (b) True
23. 23.True or false: if a wire is cut, the circuit is closed and current flows. (a) True (b) False
24. 24.🔁 What must there be for a current to flow? (a) a broken path (b) one loose end (c) a plastic gap (d) a complete loop
25. 25.🔁 Is the circuit closed or open if a wire is cut? (a) open (b) closed
26. 26.Which of these means the circuit is closed? (a) a cell is taken out (b) all wires are joined (c) a wire has come loose (d) the switch is OFF
27. 27.🔦 A circuit has a used-up (dead) cell, a good bulb and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a safety pin. Does the bulb glow? (a) Yes (b) No
28. 28.Which of these means the circuit is closed? (a) a wire has come loose (b) the bulb is unscrewed (c) the loop is complete (d) a cell is taken out
29. 29.🔦 A circuit has a new cell, a good bulb and a switch that is ON. One wire has come loose from the cell. A gap in one wire is bridged by a plastic ruler. Does the bulb glow? (a) No (b) Yes
30. 30.Which of these means the circuit is open? (a) the loop is complete (b) the switch is ON (c) the switch is OFF (d) all wires are joined
31. 31.True or false: if the switch is ON, the circuit is closed and current flows. (a) False (b) True
32. 32.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a brass key. Does the bulb glow? (a) No (b) Yes
33. 33.True or false: if a cell is taken out, the circuit is closed and current flows. (a) True (b) False
34. 34.🔦 A circuit has a new cell, a good bulb and a switch that is OFF. All the wires are firmly joined. A gap in one wire is bridged by a plastic straw. Does the bulb glow? (a) No (b) Yes
35. 35.True or false: if the switch is OFF, the circuit is closed and current flows. (a) False (b) True
36. 36.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
37. 37.🔦 A circuit has a new cell, a good bulb and a switch that is OFF. All the wires are firmly joined. A gap in one wire is bridged by a steel coin. Does the bulb glow? (a) No (b) Yes
38. 38.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a cotton thread. Does the bulb glow? (a) Yes (b) No
39. 39.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a rubber eraser. Does the bulb glow? (a) No (b) Yes
40. 40.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a metal paper clip. Does the bulb glow? (a) Yes (b) No

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