Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 899 · 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 loop is complete, the circuit is closed and current flows. (a) False (b) True
2. 2.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
3. 3.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
4. 4.Which of these means the circuit is open? (a) the loop is complete (b) all wires are joined (c) the switch is ON (d) a wire is cut
5. 5.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the base (b) the filament (c) the glass (d) the switch
6. 6.True or false: if the switch is OFF, the circuit is closed and current flows. (a) False (b) True
7. 7.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
8. 8.True or false: if a wire has come loose, the circuit is closed and current flows. (a) True (b) False
9. 9.🔁 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
10. 10.Which of these means the circuit is closed? (a) the switch is OFF (b) a wire has come loose (c) the bulb is unscrewed (d) the loop is complete
11. 11.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
12. 12.🔦 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) No (b) Yes
13. 13.Which of these means the circuit is open? (a) the switch is ON (b) the loop is complete (c) the switch is OFF (d) all wires are joined
14. 14.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) True (b) False
15. 15.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) False (b) True
16. 16.🔦 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
17. 17.True or false: if a cell is taken out, the circuit is closed and current flows. (a) False (b) True
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 wooden stick. Does the bulb glow? (a) Yes (b) No
19. 19.🔦 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
20. 20.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
21. 21.🔁 What must there be for a current to flow? (a) a plastic gap (b) a broken path (c) a complete loop (d) one loose end
22. 22.True or false: if the switch is OFF, the circuit is open and no current flows. (a) True (b) False
23. 23.True or false: if the loop is complete, the circuit is open and no current flows. (a) False (b) True
24. 24.Which of these means the circuit is closed? (a) a wire is cut (b) a cell is taken out (c) the switch is ON (d) the switch is OFF
25. 25.True or false: if all wires are joined, the circuit is closed and current flows. (a) False (b) True
26. 26.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
27. 27.🔦 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 coin. Does the bulb glow? (a) Yes (b) No
28. 28.True or false: if the switch is ON, the circuit is open and no current flows. (a) False (b) True
29. 29.🔦 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
30. 30.🔦 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 steel coin. Does the bulb glow? (a) Yes (b) No
31. 31.🔦 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
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 a paper strip. Does the bulb glow? (a) Yes (b) No
33. 33.🔁 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
34. 34.Which of these means the circuit is open? (a) all wires are joined (b) a wire has come loose (c) the switch is ON (d) the loop is complete
35. 35.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
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 an iron nail. Does the bulb glow? (a) No (b) Yes
37. 37.🔦 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
38. 38.Which of these means the circuit is closed? (a) the switch is OFF (b) all wires are joined (c) a wire has come loose (d) a cell is taken out
39. 39.🔦 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 steel spoon. Does the bulb glow? (a) No (b) Yes
40. 40.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open

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