Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 987 · 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 complete loop (c) a plastic gap (d) one loose end
2. 2.True or false: if a wire has come loose, the circuit is open and no current flows. (a) True (b) False
3. 3.True or false: if the switch is OFF, the circuit is closed and current flows. (a) True (b) False
4. 4.🔦 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 band. Does the bulb glow? (a) Yes (b) No
5. 5.Which of these means the circuit is closed? (a) a cell is taken out (b) the switch is ON (c) a wire is cut (d) a wire has come loose
6. 6.🔦 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
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. A gap in one wire is bridged by a plastic ruler. Does the bulb glow? (a) Yes (b) No
8. 8.🔦 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) No (b) Yes
9. 9.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
10. 10.True or false: if the switch is ON, the circuit is open and no current flows. (a) False (b) True
11. 11.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) both of them (b) none (c) it does not matter (d) only one
12. 12.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the filament (b) the base (c) the glass (d) the switch
13. 13.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
14. 14.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) True (b) False
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 paper strip. Does the bulb glow? (a) Yes (b) No
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 safety pin. Does the bulb glow? (a) No (b) Yes
18. 18.Which of these means the circuit is closed? (a) a wire is cut (b) the switch is OFF (c) the loop is complete (d) a cell is taken out
19. 19.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
20. 20.🔦 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 copper wire. Does the bulb glow? (a) No (b) Yes
21. 21.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
22. 22.Which of these means the circuit is open? (a) the loop is complete (b) the switch is OFF (c) all wires are joined (d) the switch is ON
23. 23.True or false: if a wire has come loose, the circuit is closed and current flows. (a) False (b) True
24. 24.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
25. 25.Which of these means the circuit is closed? (a) a wire has come loose (b) a wire is cut (c) all wires are joined (d) a cell is taken out
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) No (b) Yes
27. 27.True or false: if the loop is complete, the circuit is open and no current flows. (a) False (b) True
28. 28.🔦 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
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 steel spoon. Does the bulb glow? (a) Yes (b) No
30. 30.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) True (b) False
31. 31.🔦 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
32. 32.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
33. 33.🔦 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 woollen thread. Does the bulb glow? (a) Yes (b) No
34. 34.🔦 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 ceramic cup. Does the bulb glow? (a) No (b) Yes
35. 35.🔦 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
36. 36.🔦 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
37. 37.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
38. 38.🔁 What do we call a circuit with a break in it? (a) a series circuit (b) an open circuit (c) a closed circuit (d) a full circuit
39. 39.🔦 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 copper wire. Does the bulb glow? (a) No (b) Yes
40. 40.🔦 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

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