Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 931 · 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 bulb is unscrewed, the circuit is open and no current flows. (a) True (b) False
2. 2.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
3. 3.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
4. 4.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
5. 5.🔦 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) Yes (b) No
6. 6.🔦 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
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 closed? (a) a wire is cut (b) a cell is taken out (c) a wire has come loose (d) the switch is ON
9. 9.🔁 What must there be for a current to flow? (a) one loose end (b) a complete loop (c) a broken path (d) a plastic gap
10. 10.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
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. Does the bulb glow? (a) No (b) Yes
12. 12.True or false: if a wire has come loose, the circuit is closed and current flows. (a) False (b) True
13. 13.True or false: if the loop is complete, the circuit is open and no current flows. (a) False (b) True
14. 14.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
15. 15.🔦 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 copper wire. Does the bulb glow? (a) Yes (b) No
16. 16.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
17. 17.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
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 aluminium foil. 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 an iron nail. Does the bulb glow? (a) No (b) Yes
20. 20.True or false: if the switch is ON, the circuit is closed and current flows. (a) False (b) True
21. 21.🔦 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 coin. Does the bulb glow? (a) Yes (b) No
22. 22.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the switch (b) the base (c) the filament (d) the glass
23. 23.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) none (b) only one (c) both of them (d) it does not matter
24. 24.🔦 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
25. 25.🔦 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
26. 26.True or false: if a wire is cut, the circuit is closed and current flows. (a) True (b) False
27. 27.🔦 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 cotton thread. Does the bulb glow? (a) Yes (b) No
28. 28.🔦 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
29. 29.🔦 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
30. 30.Which of these means the circuit is open? (a) the loop is complete (b) the switch is ON (c) a wire has come loose (d) all wires are joined
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 a metal paper clip. Does the bulb glow? (a) Yes (b) No
32. 32.🔁 What do we call a circuit with a break in it? (a) an open circuit (b) a series circuit (c) a closed circuit (d) a full circuit
33. 33.🔁 Is the circuit closed or open if a wire is cut? (a) open (b) closed
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 ceramic cup. Does the bulb glow? (a) No (b) Yes
35. 35.Which of these means the circuit is open? (a) a wire is cut (b) the loop is complete (c) the switch is ON (d) all wires are joined
36. 36.True or false: if a wire is cut, the circuit is open and no current flows. (a) True (b) False
37. 37.True or false: if all wires are joined, the circuit is closed and current flows. (a) True (b) False
38. 38.🔦 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
39. 39.Which of these means the circuit is open? (a) the loop is complete (b) the switch is OFF (c) the switch is ON (d) all wires are joined
40. 40.True or false: if a cell is taken out, the circuit is closed and current flows. (a) True (b) False

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