Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 425 · 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.True or false: if the switch is ON, the circuit is closed and current flows. (a) False (b) True
2. 2.🔦 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
3. 3.True or false: if the switch is OFF, the circuit is open and no current flows. (a) False (b) True
4. 4.Which of these means the circuit is open? (a) the switch is ON (b) all wires are joined (c) the bulb is unscrewed (d) the loop is complete
5. 5.🔁 What do we call a circuit with a break in it? (a) a full circuit (b) a closed circuit (c) a series circuit (d) an open circuit
6. 6.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the filament (c) the base (d) the switch
7. 7.🔁 What must there be for a current to flow? (a) a plastic gap (b) a broken path (c) one loose end (d) a complete loop
8. 8.🔦 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
9. 9.Which of these means the circuit is closed? (a) the switch is OFF (b) a wire has come loose (c) the switch is ON (d) the bulb is unscrewed
10. 10.True or false: if the loop is complete, the circuit is closed and current flows. (a) False (b) True
11. 11.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
12. 12.Which of these means the circuit is open? (a) the loop is complete (b) all wires are joined (c) a wire is cut (d) the switch is ON
13. 13.🔦 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 steel coin. Does the bulb glow? (a) No (b) Yes
14. 14.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
15. 15.Which of these means the circuit is closed? (a) a wire is cut (b) a cell is taken out (c) the bulb is unscrewed (d) the loop is complete
16. 16.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
17. 17.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
18. 18.🔦 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 brass key. Does the bulb glow? (a) Yes (b) No
19. 19.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) the switch is OFF (c) all wires are joined (d) a wire is cut
20. 20.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) none (b) both of them (c) it does not matter (d) only one
21. 21.🔦 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) No (b) Yes
22. 22.🔦 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
23. 23.🔦 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 safety pin. Does the bulb glow? (a) Yes (b) No
24. 24.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
25. 25.🔦 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 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 an iron nail. Does the bulb glow? (a) No (b) Yes
27. 27.True or false: if a cell is taken out, the circuit is closed and current flows. (a) True (b) False
28. 28.True or false: if a wire is cut, the circuit is open and no current flows. (a) True (b) False
29. 29.True or false: if the switch is ON, the circuit is open and no current flows. (a) False (b) True
30. 30.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
31. 31.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
32. 32.True or false: if a wire has come loose, the circuit is closed and current flows. (a) True (b) False
33. 33.True or false: if all wires are joined, the circuit is open and no current flows. (a) False (b) True
34. 34.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
35. 35.🔦 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) Yes (b) No
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 paper strip. Does the bulb glow? (a) No (b) Yes
37. 37.Which of these means the circuit is open? (a) the loop is complete (b) a wire has come loose (c) all wires are joined (d) the switch is ON
38. 38.🔦 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
39. 39.True or false: if the switch is OFF, the circuit is closed and current flows. (a) True (b) False
40. 40.Which of these means the circuit is open? (a) all wires are joined (b) the switch is ON (c) the loop is complete (d) a cell is taken out

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