Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 452 · 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. Does the bulb glow? (a) No (b) Yes
2. 2.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
3. 3.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) it does not matter (b) both of them (c) only one (d) none
4. 4.True or false: if a wire is cut, the circuit is open and no current flows. (a) True (b) False
5. 5.True or false: if a wire is cut, the circuit is closed and current flows. (a) True (b) False
6. 6.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the base (b) the switch (c) the glass (d) the filament
7. 7.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
8. 8.Which of these means the circuit is open? (a) all wires are joined (b) the bulb is unscrewed (c) the switch is ON (d) the loop is complete
9. 9.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
10. 10.🔦 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
11. 11.🔦 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
12. 12.🔁 What must there be for a current to flow? (a) a complete loop (b) a plastic gap (c) one loose end (d) a broken path
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 spoon. Does the bulb glow? (a) No (b) Yes
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 woollen thread. Does the bulb glow? (a) Yes (b) No
15. 15.🔁 What do we call a circuit with a break in it? (a) a full circuit (b) a series circuit (c) an open circuit (d) a closed circuit
16. 16.True or false: if the switch is ON, the circuit is open and no current flows. (a) False (b) True
17. 17.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) a cell is taken out (c) a wire has come loose (d) the loop is complete
18. 18.True or false: if the switch is OFF, the circuit is closed and current flows. (a) False (b) True
19. 19.True or false: if a wire has come loose, the circuit is open and no current flows. (a) True (b) False
20. 20.True or false: if a cell is taken out, the circuit is closed and current flows. (a) True (b) False
21. 21.True or false: if a cell is taken out, the circuit is open and no current flows. (a) False (b) True
22. 22.🔦 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 copper wire. Does the bulb glow? (a) No (b) Yes
23. 23.Which of these means the circuit is open? (a) all wires are joined (b) the switch is ON (c) a wire is cut (d) the loop is complete
24. 24.Which of these means the circuit is closed? (a) a cell is taken out (b) a wire has come loose (c) the switch is ON (d) the bulb is unscrewed
25. 25.🔦 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
26. 26.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
27. 27.Which of these means the circuit is open? (a) the switch is ON (b) the switch is OFF (c) all wires are joined (d) the loop is complete
28. 28.🔦 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
29. 29.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) True (b) False
30. 30.True or false: if the switch is OFF, the circuit is open and no current flows. (a) False (b) True
31. 31.🔦 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 ruler. Does the bulb glow? (a) Yes (b) No
32. 32.🔦 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) No (b) Yes
33. 33.Which of these means the circuit is closed? (a) a wire has come loose (b) the bulb is unscrewed (c) a cell is taken out (d) all wires are joined
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 aluminium foil. Does the bulb glow? (a) No (b) Yes
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) No (b) Yes
36. 36.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
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 rubber eraser. Does the bulb glow? (a) No (b) Yes
38. 38.🔦 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 dry cork. Does the bulb glow? (a) No (b) Yes
39. 39.True or false: if all wires are joined, the circuit is open and no current flows. (a) True (b) False
40. 40.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed

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