Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 109 · 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. 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
2. 2.🔦 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
3. 3.True or false: if all wires are joined, the circuit is open and no current flows. (a) True (b) False
4. 4.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
5. 5.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
6. 6.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
7. 7.🔁 What must there be for a current to flow? (a) a complete loop (b) one loose end (c) a plastic gap (d) a broken path
8. 8.🔦 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
9. 9.Which of these means the circuit is closed? (a) a cell is taken out (b) the switch is OFF (c) a wire is cut (d) all wires are joined
10. 10.🔁 Is the circuit closed or open if a wire is cut? (a) open (b) closed
11. 11.True or false: if the switch is OFF, the circuit is closed and current flows. (a) False (b) True
12. 12.🔦 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
13. 13.Which of these means the circuit is closed? (a) a wire has come loose (b) the switch is ON (c) a cell is taken out (d) the bulb is unscrewed
14. 14.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
15. 15.Which of these means the circuit is open? (a) the loop is complete (b) all wires are joined (c) the switch is ON (d) a wire is cut
16. 16.Which of these means the circuit is closed? (a) the loop is complete (b) a wire is cut (c) a wire has come loose (d) the switch is OFF
17. 17.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the filament (c) the base (d) the switch
18. 18.🔦 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
19. 19.🔦 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
20. 20.🔁 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
21. 21.Which of these means the circuit is open? (a) a cell is taken out (b) the loop is complete (c) all wires are joined (d) the switch is ON
22. 22.🔁 Is the circuit closed or open if the switch is OFF? (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 aluminium foil. Does the bulb glow? (a) Yes (b) No
24. 24.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
25. 25.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) False (b) True
26. 26.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) True (b) False
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. Does the bulb glow? (a) Yes (b) No
28. 28.True or false: if a cell is taken out, the circuit is open and no current flows. (a) False (b) True
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 a brass key. Does the bulb glow? (a) No (b) Yes
30. 30.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
31. 31.True or false: if the switch is ON, the circuit is closed and 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 plastic straw. Does the bulb glow? (a) Yes (b) No
33. 33.True or false: if the loop is complete, the circuit is closed and current flows. (a) True (b) False
34. 34.🔁 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) both of them (d) only one
35. 35.True or false: if a wire has come loose, the circuit is open and no current flows. (a) False (b) True
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 metal paper clip. 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 a woollen thread. Does the bulb glow? (a) Yes (b) No
38. 38.True or false: if all wires are joined, the circuit is closed and current flows. (a) False (b) True
39. 39.🔦 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) No (b) Yes
40. 40.True or false: if the switch is OFF, the circuit is open and no current flows. (a) False (b) True

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