Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 718 · 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 closed circuit (b) an open circuit (c) a series circuit (d) a full circuit
2. 2.Which of these means the circuit is open? (a) the loop is complete (b) the switch is ON (c) a wire is cut (d) all wires are joined
3. 3.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the switch (c) the filament (d) the base
4. 4.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
5. 5.True or false: if all wires are joined, the circuit is closed and current flows. (a) True (b) False
6. 6.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
7. 7.🔁 What must there be for a current to flow? (a) a plastic gap (b) a broken path (c) a complete loop (d) one loose end
8. 8.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) it does not matter (b) both of them (c) only one (d) none
9. 9.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 has come loose
10. 10.🔦 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) Yes (b) No
11. 11.Which of these means the circuit is closed? (a) a cell is taken out (b) the bulb is unscrewed (c) all wires are joined (d) a wire has come loose
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.🔦 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
14. 14.Which of these means the circuit is open? (a) the switch is ON (b) all wires are joined (c) the loop is complete (d) the switch is OFF
15. 15.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
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 rubber eraser. Does the bulb glow? (a) Yes (b) No
17. 17.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) a wire has come loose (c) the switch is OFF (d) the switch is ON
18. 18.🔦 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
19. 19.True or false: if all wires are joined, the circuit is open and no current flows. (a) True (b) False
20. 20.True or false: if the loop is complete, the circuit is closed and current flows. (a) False (b) True
21. 21.🔦 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 metal paper clip. Does the bulb glow? (a) No (b) Yes
22. 22.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
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 dry cork. Does the bulb glow? (a) Yes (b) No
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. A gap in one wire is bridged by a metal paper clip. Does the bulb glow? (a) Yes (b) No
25. 25.🔦 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 aluminium foil. Does the bulb glow? (a) No (b) Yes
26. 26.🔦 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
27. 27.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) True (b) False
28. 28.True or false: if the loop is complete, the circuit is open and no current flows. (a) False (b) True
29. 29.Which of these means the circuit is open? (a) all wires are joined (b) the switch is ON (c) the loop is complete (d) the bulb is unscrewed
30. 30.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
31. 31.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
32. 32.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) False (b) True
33. 33.True or false: if the switch is ON, the circuit is closed and current flows. (a) False (b) True
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. A gap in one wire is bridged by a graphite rod. Does the bulb glow? (a) Yes (b) No
35. 35.Which of these means the circuit is closed? (a) a cell is taken out (b) the loop is complete (c) the bulb is unscrewed (d) a wire has come loose
36. 36.🔦 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
37. 37.🔦 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
38. 38.True or false: if a wire is cut, the circuit is open and no current flows. (a) False (b) True
39. 39.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
40. 40.🔦 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

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