Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 83 · 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.🔦 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
2. 2.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) False (b) True
3. 3.True or false: if the switch is ON, the circuit is closed and current flows. (a) True (b) False
4. 4.True or false: if a wire is cut, the circuit is open and no current flows. (a) True (b) False
5. 5.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 bulb is unscrewed
6. 6.Which of these means the circuit is open? (a) the switch is ON (b) all wires are joined (c) the loop is complete (d) a cell is taken out
7. 7.True or false: if the switch is OFF, the circuit is closed and current flows. (a) True (b) False
8. 8.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
9. 9.🔦 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
10. 10.True or false: if a wire has come loose, the circuit is closed and current flows. (a) True (b) False
11. 11.🔦 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
12. 12.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
13. 13.True or false: if the switch is ON, the circuit is open and no current flows. (a) False (b) True
14. 14.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) a wire is cut (c) the switch is ON (d) a wire has come loose
15. 15.Which of these means the circuit is open? (a) a wire has come loose (b) the loop is complete (c) all wires are joined (d) the switch is ON
16. 16.True or false: if all wires are joined, the circuit is open and no current flows. (a) False (b) True
17. 17.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
18. 18.Which of these means the circuit is closed? (a) a wire has come loose (b) the switch is OFF (c) the loop is complete (d) a wire is cut
19. 19.True or false: if the loop is complete, the circuit is open and no current flows. (a) False (b) True
20. 20.🔁 What do we call a circuit with a break in it? (a) a series circuit (b) a full circuit (c) a closed circuit (d) an open circuit
21. 21.🔦 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 plastic straw. Does the bulb glow? (a) Yes (b) No
22. 22.Which of these means the circuit is open? (a) all wires are joined (b) the switch is ON (c) the loop is complete (d) the switch is OFF
23. 23.True or false: if a cell is taken out, the circuit is open and no current flows. (a) False (b) True
24. 24.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
25. 25.🔦 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
26. 26.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
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 dry cork. Does the bulb glow? (a) Yes (b) No
28. 28.True or false: if the loop is complete, the circuit is closed and current flows. (a) False (b) True
29. 29.🔦 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
30. 30.🔁 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
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 rubber eraser. Does the bulb glow? (a) No (b) Yes
32. 32.🔦 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) Yes (b) No
33. 33.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the base (b) the glass (c) the filament (d) the switch
34. 34.🔦 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 cotton thread. Does the bulb glow? (a) Yes (b) No
35. 35.True or false: if all wires are joined, the circuit is closed and current flows. (a) True (b) False
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 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 ceramic cup. Does the bulb glow? (a) No (b) Yes
38. 38.🔦 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 plastic straw. Does the bulb glow? (a) Yes (b) No
39. 39.🔁 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
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 steel spoon. Does the bulb glow? (a) No (b) Yes

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