Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 888 · 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.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
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 a woollen thread. Does the bulb glow? (a) No (b) Yes
3. 3.True or false: if a wire has come loose, the circuit is closed and current flows. (a) False (b) True
4. 4.🔁 What must there be for a current to flow? (a) a complete loop (b) one loose end (c) a broken path (d) a plastic gap
5. 5.🔦 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
6. 6.🔦 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 aluminium foil. Does the bulb glow? (a) Yes (b) No
7. 7.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
8. 8.🔁 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
9. 9.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the switch (b) the glass (c) the base (d) the filament
10. 10.🔦 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
11. 11.Which of these means the circuit is closed? (a) a wire is cut (b) the loop is complete (c) the bulb is unscrewed (d) a wire has come loose
12. 12.Which of these means the circuit is open? (a) all wires are joined (b) the loop is complete (c) the switch is OFF (d) the switch is ON
13. 13.🔦 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
14. 14.Which of these means the circuit is closed? (a) the switch is OFF (b) the switch is ON (c) a wire is cut (d) a cell is taken out
15. 15.🔦 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 steel spoon. Does the bulb glow? (a) No (b) Yes
16. 16.True or false: if the switch is ON, the circuit is open and no current flows. (a) False (b) True
17. 17.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
18. 18.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
19. 19.True or false: if the switch is OFF, the circuit is closed and current flows. (a) True (b) False
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 plastic ruler. Does the bulb glow? (a) No (b) Yes
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 a metal paper clip. Does the bulb glow? (a) Yes (b) No
22. 22.🔦 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
23. 23.🔦 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) Yes (b) No
24. 24.🔦 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 plastic straw. Does the bulb glow? (a) No (b) Yes
25. 25.🔦 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
26. 26.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
27. 27.True or false: if the switch is OFF, the circuit is open and no current flows. (a) False (b) True
28. 28.Which of these means the circuit is closed? (a) all wires are joined (b) the switch is OFF (c) the bulb is unscrewed (d) a wire has come loose
29. 29.True or false: if the loop is complete, the circuit is open and no current flows. (a) False (b) True
30. 30.True or false: if a cell is taken out, the circuit is closed and current flows. (a) True (b) False
31. 31.Which of these means the circuit is open? (a) the switch is ON (b) the bulb is unscrewed (c) all wires are joined (d) the loop is complete
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 steel spoon. Does the bulb glow? (a) Yes (b) No
33. 33.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
34. 34.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) only one (b) none (c) it does not matter (d) both of them
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. A gap in one wire is bridged by a wooden stick. Does the bulb glow? (a) Yes (b) No
36. 36.True or false: if all wires are joined, the circuit is open and no current flows. (a) True (b) False
37. 37.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
38. 38.Which of these means the circuit is open? (a) the loop is complete (b) the switch is ON (c) a cell is taken out (d) all wires are joined
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 ceramic cup. Does the bulb glow? (a) No (b) Yes
40. 40.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 wire is cut

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