Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 45 · 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 do we call a circuit with a break in it? (a) a series circuit (b) a full circuit (c) an open circuit (d) a closed circuit
2. 2.Which of these means the circuit is closed? (a) the loop is complete (b) the switch is OFF (c) a wire has come loose (d) the bulb is unscrewed
3. 3.Which of these means the circuit is open? (a) the switch is ON (b) all wires are joined (c) the loop is complete (d) a cell is taken out
4. 4.True or false: if the switch is OFF, the circuit is closed and current flows. (a) True (b) False
5. 5.True or false: if a cell is taken out, the circuit is open and no current flows. (a) False (b) True
6. 6.🔦 A circuit has a used-up (dead) cell, a good bulb and a switch that is ON. All the wires are firmly joined. Does the bulb glow? (a) No (b) Yes
7. 7.🔦 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 aluminium foil. Does the bulb glow? (a) Yes (b) No
8. 8.🔁 Is the circuit closed or open if a wire is cut? (a) open (b) closed
9. 9.🔦 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
10. 10.🔦 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) Yes (b) No
11. 11.True or false: if the switch is ON, the circuit is closed and current flows. (a) True (b) False
12. 12.🔦 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 an iron nail. Does the bulb glow? (a) No (b) Yes
13. 13.Which of these means the circuit is closed? (a) a cell is taken out (b) all wires are joined (c) a wire is cut (d) the bulb is unscrewed
14. 14.🔦 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 woollen thread. Does the bulb glow? (a) No (b) Yes
15. 15.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
16. 16.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the base (c) the switch (d) the filament
17. 17.🔦 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 rubber band. Does the bulb glow? (a) Yes (b) No
18. 18.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
19. 19.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
20. 20.Which of these means the circuit is open? (a) the bulb is unscrewed (b) all wires are joined (c) the loop is complete (d) the switch is ON
21. 21.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) only one (b) both of them (c) it does not matter (d) none
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. Does the bulb glow? (a) No (b) Yes
23. 23.🔦 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) No (b) Yes
24. 24.🔦 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
25. 25.True or false: if a wire has come loose, the circuit is closed and current flows. (a) True (b) False
26. 26.True or false: if a wire is cut, the circuit is closed and current flows. (a) True (b) False
27. 27.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) the switch is ON (c) a cell is taken out (d) the switch is OFF
28. 28.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
29. 29.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
30. 30.🔁 What must there be for a current to flow? (a) one loose end (b) a plastic gap (c) a broken path (d) a complete loop
31. 31.🔦 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
32. 32.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
33. 33.True or false: if all wires are joined, the circuit is closed and current flows. (a) False (b) True
34. 34.🔦 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
35. 35.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) False (b) True
36. 36.🔦 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 an iron nail. Does the bulb glow? (a) Yes (b) No
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 graphite rod. Does the bulb glow? (a) No (b) Yes
38. 38.Which of these means the circuit is open? (a) the switch is ON (b) all wires are joined (c) the loop is complete (d) a wire is cut
39. 39.🔦 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 brass key. Does the bulb glow? (a) Yes (b) No
40. 40.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed

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