Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 835 · 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.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the base (b) the glass (c) the filament (d) the switch
2. 2.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
3. 3.Which of these means the circuit is closed? (a) a wire has come loose (b) a cell is taken out (c) the loop is complete (d) the bulb is unscrewed
4. 4.🔦 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
5. 5.🔁 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
6. 6.Which of these means the circuit is closed? (a) a wire has come loose (b) all wires are joined (c) a wire is cut (d) the switch is OFF
7. 7.True or false: if a wire is cut, the circuit is open and no current flows. (a) False (b) True
8. 8.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) False (b) True
9. 9.🔦 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 paper strip. Does the bulb glow? (a) No (b) Yes
10. 10.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
11. 11.🔦 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 safety pin. Does the bulb glow? (a) No (b) Yes
12. 12.True or false: if the switch is OFF, the circuit is open and no current flows. (a) True (b) False
13. 13.🔦 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
14. 14.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
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 woollen thread. Does the bulb glow? (a) Yes (b) No
16. 16.Which of these means the circuit is open? (a) the loop is complete (b) a wire has come loose (c) the switch is ON (d) all wires are joined
17. 17.🔦 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) No (b) Yes
18. 18.🔦 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 an iron nail. Does the bulb glow? (a) Yes (b) No
19. 19.🔦 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) No (b) Yes
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. Does the bulb glow? (a) No (b) Yes
21. 21.True or false: if the switch is OFF, the circuit is closed and current flows. (a) False (b) True
22. 22.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) both of them (b) it does not matter (c) only one (d) none
23. 23.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) False (b) True
24. 24.🔦 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
25. 25.True or false: if a cell is taken out, the circuit is open and no current flows. (a) False (b) True
26. 26.True or false: if the switch is ON, the circuit is closed and current flows. (a) True (b) False
27. 27.🔁 What must there be for a current to flow? (a) a plastic gap (b) a complete loop (c) a broken path (d) one loose end
28. 28.True or false: if the switch is ON, the circuit is open and no current flows. (a) False (b) True
29. 29.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
30. 30.Which of these means the circuit is open? (a) a cell is taken out (b) the loop is complete (c) all wires are joined (d) the switch is ON
31. 31.🔦 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
32. 32.True or false: if the loop is complete, the circuit is open and no current flows. (a) True (b) False
33. 33.Which of these means the circuit is closed? (a) the switch is OFF (b) the switch is ON (c) a wire is cut (d) the bulb is unscrewed
34. 34.True or false: if a wire has come loose, the circuit is closed and current flows. (a) False (b) True
35. 35.🔦 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 ruler. Does the bulb glow? (a) No (b) Yes
36. 36.🔦 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
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 glass marble. Does the bulb glow? (a) No (b) Yes
38. 38.🔦 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 an iron nail. Does the bulb glow? (a) Yes (b) No
39. 39.🔦 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
40. 40.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open

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