Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 405 · 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.🔁 What must there be for a current to flow? (a) a broken path (b) a plastic gap (c) one loose end (d) a complete loop
2. 2.True or false: if all wires are joined, the circuit is closed and current flows. (a) False (b) True
3. 3.Which of these means the circuit is closed? (a) a wire is cut (b) a wire has come loose (c) the switch is ON (d) a cell is taken out
4. 4.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) True (b) False
5. 5.Which of these means the circuit is closed? (a) a wire is cut (b) a cell is taken out (c) the bulb is unscrewed (d) the loop is complete
6. 6.🔦 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) Yes (b) No
7. 7.Which of these means the circuit is closed? (a) a cell is taken out (b) a wire is cut (c) all wires are joined (d) the bulb is unscrewed
8. 8.Which of these means the circuit is open? (a) all wires are joined (b) the switch is ON (c) the switch is OFF (d) the loop is complete
9. 9.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
10. 10.🔦 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) Yes (b) No
11. 11.🔦 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 copper wire. Does the bulb glow? (a) Yes (b) No
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 all wires are joined? (a) open (b) closed
14. 14.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
15. 15.True or false: if the switch is OFF, the circuit is closed and current flows. (a) False (b) True
16. 16.🔦 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 an iron nail. Does the bulb glow? (a) No (b) Yes
17. 17.🔦 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 steel spoon. Does the bulb glow? (a) Yes (b) No
18. 18.🔦 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) Yes (b) No
19. 19.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
20. 20.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
21. 21.🔦 A circuit has a new cell, a bulb with a broken filament 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) Yes (b) No
22. 22.🔦 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 brass key. Does the bulb glow? (a) No (b) Yes
23. 23.True or false: if all wires are joined, the circuit is open and no current flows. (a) False (b) True
24. 24.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) False (b) True
25. 25.True or false: if a wire has come loose, the circuit is closed and current flows. (a) False (b) True
26. 26.🔦 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 plastic straw. Does the bulb glow? (a) No (b) Yes
27. 27.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
28. 28.True or false: if the switch is ON, the circuit is open and no current flows. (a) True (b) False
29. 29.True or false: if a wire has come loose, the circuit is open and no current flows. (a) True (b) False
30. 30.🔦 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 plastic ruler. Does the bulb glow? (a) No (b) Yes
31. 31.True or false: if the switch is OFF, the circuit is open and no current flows. (a) True (b) False
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 wooden stick. Does the bulb glow? (a) No (b) Yes
33. 33.🔁 What do we call a circuit with a break in it? (a) a closed circuit (b) a full circuit (c) an open circuit (d) a series circuit
34. 34.🔦 A circuit has a new cell, a bulb with a broken filament and a switch that is ON. All the wires are firmly joined. Does the bulb glow? (a) Yes (b) No
35. 35.True or false: if the loop is complete, the circuit is open and no current flows. (a) True (b) False
36. 36.True or false: if a wire is cut, the circuit is open and no current flows. (a) False (b) True
37. 37.🔦 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) Yes (b) No
38. 38.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) it does not matter (b) none (c) only one (d) both of them
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 graphite rod. Does the bulb glow? (a) Yes (b) No
40. 40.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed

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