Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 376 · 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.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the base (c) the filament (d) the switch
2. 2.🔁 What do we call a circuit with a break in it? (a) an open circuit (b) a series circuit (c) a full circuit (d) a closed circuit
3. 3.🔦 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) Yes (b) No
4. 4.🔦 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) Yes (b) No
5. 5.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
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 ON. One wire has come loose from the cell. Does the bulb glow? (a) No (b) Yes
8. 8.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
9. 9.Which of these means the circuit is open? (a) all wires are joined (b) the switch is OFF (c) the loop is complete (d) the switch is ON
10. 10.🔁 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
11. 11.True or false: if the switch is ON, the circuit is open and no current flows. (a) False (b) True
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 a plastic straw. Does the bulb glow? (a) Yes (b) No
13. 13.True or false: if the switch is ON, the circuit is closed and current flows. (a) True (b) False
14. 14.🔦 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 glass marble. Does the bulb glow? (a) No (b) Yes
15. 15.Which of these means the circuit is closed? (a) a wire is cut (b) all wires are joined (c) a cell is taken out (d) the bulb is unscrewed
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 cotton thread. Does the bulb glow? (a) Yes (b) No
17. 17.Which of these means the circuit is open? (a) the switch is ON (b) the loop is complete (c) a wire has come loose (d) all wires are joined
18. 18.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) the switch is OFF (c) the switch is ON (d) a cell is taken out
19. 19.Which of these means the circuit is open? (a) the loop is complete (b) all wires are joined (c) a cell is taken out (d) the switch is ON
20. 20.True or false: if the switch is OFF, 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 OFF. All the wires are firmly joined. A gap in one wire is bridged by aluminium foil. Does the bulb glow? (a) No (b) Yes
22. 22.True or false: if a wire has come loose, the circuit is open and no current flows. (a) False (b) True
23. 23.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
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) No (b) Yes
25. 25.🔦 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
26. 26.🔦 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) Yes (b) No
27. 27.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
28. 28.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
29. 29.🔦 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 an iron nail. Does the bulb glow? (a) Yes (b) No
30. 30.True or false: if all wires are joined, the circuit is open and no current flows. (a) True (b) False
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 steel spoon. Does the bulb glow? (a) Yes (b) No
32. 32.🔦 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) Yes (b) No
33. 33.True or false: if a wire is cut, the circuit is open and no current flows. (a) False (b) True
34. 34.True or false: if the loop is complete, the circuit is open and no current flows. (a) False (b) True
35. 35.True or false: if a cell is taken out, the circuit is closed and current flows. (a) True (b) False
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 an iron nail. Does the bulb glow? (a) No (b) Yes
37. 37.🔦 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 band. Does the bulb glow? (a) Yes (b) No
38. 38.🔁 What must there be for a current to flow? (a) a complete loop (b) a plastic gap (c) one loose end (d) a broken path
39. 39.True or false: if all wires are joined, the circuit is closed and current flows. (a) True (b) False
40. 40.🔦 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 steel coin. Does the bulb glow? (a) Yes (b) No

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