Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 741 · 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 switch is ON, the circuit is closed and current flows. (a) False (b) True
2. 2.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
3. 3.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) only one (b) none (c) both of them (d) it does not matter
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 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 an iron nail. Does the bulb glow? (a) Yes (b) No
6. 6.Which of these means the circuit is closed? (a) a wire is cut (b) a wire has come loose (c) the switch is ON (d) the bulb is unscrewed
7. 7.🔁 What must there be for a current to flow? (a) a plastic gap (b) one loose end (c) a broken path (d) a complete loop
8. 8.🔦 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
9. 9.🔦 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
10. 10.Which of these means the circuit is closed? (a) all wires are joined (b) the switch is OFF (c) a wire has come loose (d) a cell is taken out
11. 11.Which of these means the circuit is open? (a) a wire has come loose (b) all wires are joined (c) the loop is complete (d) the switch is ON
12. 12.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
13. 13.True or false: if a cell is taken out, the circuit is closed and current flows. (a) True (b) False
14. 14.🔦 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) No (b) Yes
15. 15.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the filament (b) the glass (c) the switch (d) the base
16. 16.Which of these means the circuit is closed? (a) the loop is complete (b) a wire has come loose (c) the bulb is unscrewed (d) a wire is cut
17. 17.True or false: if a cell is taken out, the circuit is open and no current flows. (a) True (b) False
18. 18.🔁 Is the circuit closed or open if a wire is cut? (a) open (b) closed
19. 19.🔦 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 rubber band. Does the bulb glow? (a) No (b) Yes
20. 20.🔦 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
21. 21.🔁 What do we call a circuit with a break in it? (a) a closed circuit (b) a full circuit (c) an open circuit (d) a series circuit
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 aluminium foil. Does the bulb glow? (a) Yes (b) No
23. 23.True or false: if a wire is cut, the circuit is closed and current flows. (a) False (b) True
24. 24.True or false: if the loop is complete, the circuit is open and no current flows. (a) True (b) False
25. 25.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
26. 26.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
27. 27.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) False (b) True
28. 28.🔦 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
29. 29.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
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 copper wire. Does the bulb glow? (a) Yes (b) No
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 an iron nail. Does the bulb glow? (a) Yes (b) No
32. 32.True or false: if the loop is complete, the circuit is closed and current flows. (a) True (b) False
33. 33.🔦 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 brass key. Does the bulb glow? (a) Yes (b) No
34. 34.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) False (b) True
35. 35.🔦 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
36. 36.True or false: if a wire has come loose, the circuit is closed and current flows. (a) True (b) False
37. 37.🔦 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) No (b) Yes
38. 38.True or false: if a wire has come loose, the circuit is open and no current flows. (a) False (b) True
39. 39.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
40. 40.🔦 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 wooden stick. Does the bulb glow? (a) No (b) Yes

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