Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 79 · 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.Which of these means the circuit is closed? (a) a wire is cut (b) all wires are joined (c) a wire has come loose (d) the switch is OFF
2. 2.Which of these means the circuit is closed? (a) the switch is ON (b) a wire has come loose (c) a wire is cut (d) the bulb is unscrewed
3. 3.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
4. 4.🔦 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 plastic straw. Does the bulb glow? (a) Yes (b) No
5. 5.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
6. 6.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) True (b) False
7. 7.🔦 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 plastic ruler. Does the bulb glow? (a) No (b) Yes
8. 8.True or false: if the loop is complete, the circuit is open and no current flows. (a) False (b) True
9. 9.🔦 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
10. 10.Which of these means the circuit is open? (a) all wires are joined (b) the loop is complete (c) the switch is ON (d) a cell is taken out
11. 11.🔁 Is the circuit closed or open if a wire is cut? (a) open (b) closed
12. 12.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
13. 13.🔦 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 woollen thread. Does the bulb glow? (a) Yes (b) No
14. 14.🔦 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 coin. Does the bulb glow? (a) No (b) Yes
15. 15.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the base (c) the switch (d) the filament
16. 16.True or false: if the loop is complete, the circuit is closed and current flows. (a) True (b) False
17. 17.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) none (b) it does not matter (c) only one (d) both of them
18. 18.🔁 What must there be for a current to flow? (a) one loose end (b) a broken path (c) a plastic gap (d) a complete loop
19. 19.Which of these means the circuit is open? (a) a wire has come loose (b) the loop is complete (c) the switch is ON (d) all wires are joined
20. 20.🔦 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
21. 21.🔦 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
22. 22.True or false: if a wire is cut, the circuit is closed and current flows. (a) False (b) True
23. 23.🔦 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
24. 24.True or false: if a wire has come loose, the circuit is open and no current flows. (a) True (b) False
25. 25.Which of these means the circuit is open? (a) the loop is complete (b) the switch is ON (c) the switch is OFF (d) all wires are joined
26. 26.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) the loop is complete (c) the switch is OFF (d) a wire has come loose
27. 27.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
28. 28.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
29. 29.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
30. 30.🔦 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
31. 31.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
32. 32.🔁 What do we call a circuit with a break in it? (a) a series circuit (b) a closed circuit (c) an open circuit (d) a full circuit
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 aluminium foil. Does the bulb glow? (a) No (b) Yes
34. 34.🔦 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
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 metal paper clip. Does the bulb glow? (a) No (b) Yes
36. 36.🔦 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 coin. Does the bulb glow? (a) No (b) Yes
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 aluminium foil. Does the bulb glow? (a) Yes (b) No
38. 38.True or false: if the switch is OFF, the circuit is open and no current flows. (a) False (b) True
39. 39.🔦 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
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 cotton thread. Does the bulb glow? (a) Yes (b) No

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