Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 858 · 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 open? (a) all wires are joined (b) the loop is complete (c) a cell is taken out (d) the switch is ON
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 a wire has come loose, the circuit is closed and current flows. (a) False (b) True
4. 4.🔦 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 safety pin. Does the bulb glow? (a) Yes (b) No
5. 5.🔦 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 plastic ruler. Does the bulb glow? (a) Yes (b) No
6. 6.🔁 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
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 copper wire. Does the bulb glow? (a) No (b) Yes
8. 8.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the base (b) the glass (c) the filament (d) the switch
9. 9.True or false: if a wire is cut, the circuit is open and no current flows. (a) False (b) True
10. 10.Which of these means the circuit is closed? (a) a cell is taken out (b) the switch is OFF (c) all wires are joined (d) a wire is cut
11. 11.True or false: if all wires are joined, the circuit is closed and current flows. (a) True (b) False
12. 12.🔦 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
13. 13.True or false: if the switch is ON, the circuit is closed and current flows. (a) False (b) True
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 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
17. 17.Which of these means the circuit is open? (a) the switch is OFF (b) the switch is ON (c) all wires are joined (d) the loop is complete
18. 18.🔦 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) Yes (b) No
19. 19.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
20. 20.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
21. 21.True or false: if a cell is taken out, the circuit is closed and current flows. (a) True (b) False
22. 22.True or false: if all wires are joined, the circuit is open and no current flows. (a) False (b) True
23. 23.🔦 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
24. 24.True or false: if the switch is ON, the circuit is open and no current flows. (a) False (b) True
25. 25.True or false: if the switch is OFF, the circuit is open and no current flows. (a) True (b) False
26. 26.True or false: if a wire is cut, the circuit is closed and current flows. (a) False (b) True
27. 27.🔁 What do we call a circuit with a break in it? (a) a full circuit (b) an open circuit (c) a series circuit (d) a closed circuit
28. 28.🔦 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 wooden stick. Does the bulb glow? (a) No (b) Yes
29. 29.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
30. 30.🔦 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) Yes (b) No
31. 31.True or false: if the switch is OFF, the circuit is closed and current flows. (a) False (b) True
32. 32.🔁 What must there be for a current to flow? (a) a broken path (b) one loose end (c) a complete loop (d) a plastic gap
33. 33.🔦 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 rubber eraser. 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 steel spoon. Does the bulb glow? (a) Yes (b) No
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 glass marble. Does the bulb glow? (a) Yes (b) No
36. 36.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
37. 37.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) False (b) True
38. 38.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
39. 39.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
40. 40.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

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