Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 939 · 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 bulb has two contacts. How many must be joined into the loop for it to glow? (a) both of them (b) only one (c) none (d) it does not matter
2. 2.🔦 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 straw. Does the bulb glow? (a) No (b) Yes
3. 3.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 switch is ON
4. 4.🔦 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
5. 5.🔁 What do we call a circuit with a break in it? (a) a closed circuit (b) an open circuit (c) a series circuit (d) a full circuit
6. 6.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) False (b) True
7. 7.🔦 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 paper strip. Does the bulb glow? (a) No (b) Yes
8. 8.True or false: if a cell is taken out, the circuit is open and no current flows. (a) False (b) True
9. 9.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
10. 10.🔦 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 plastic ruler. Does the bulb glow? (a) Yes (b) No
11. 11.Which of these means the circuit is open? (a) all wires are joined (b) the loop is complete (c) the switch is OFF (d) the switch is ON
12. 12.🔦 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
13. 13.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
14. 14.Which of these means the circuit is closed? (a) the switch is OFF (b) the bulb is unscrewed (c) a wire is cut (d) the loop is complete
15. 15.🔦 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 graphite rod. Does the bulb glow? (a) No (b) Yes
16. 16.True or false: if all wires are joined, the circuit is open and no current flows. (a) True (b) False
17. 17.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 bulb is unscrewed
18. 18.🔦 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 paper strip. Does the bulb glow? (a) No (b) Yes
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 an iron nail. Does the bulb glow? (a) No (b) Yes
20. 20.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the filament (b) the base (c) the glass (d) the switch
21. 21.Which of these means the circuit is closed? (a) all wires are joined (b) a wire has come loose (c) a wire is cut (d) the switch is OFF
22. 22.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
23. 23.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
24. 24.True or false: if a cell is taken out, the circuit is closed and current flows. (a) False (b) True
25. 25.🔦 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
26. 26.True or false: if the loop is complete, the circuit is open and no current flows. (a) False (b) True
27. 27.🔦 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 brass key. Does the bulb glow? (a) No (b) Yes
28. 28.🔦 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
29. 29.Which of these means the circuit is open? (a) the loop is complete (b) all wires are joined (c) a wire is cut (d) the switch is ON
30. 30.True or false: if the switch is ON, the circuit is open and no current flows. (a) True (b) False
31. 31.Which of these means the circuit is open? (a) the switch is ON (b) a wire has come loose (c) the loop is complete (d) all wires are joined
32. 32.🔦 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 aluminium foil. Does the bulb glow? (a) Yes (b) No
33. 33.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) False (b) True
34. 34.🔦 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 ceramic cup. Does the bulb glow? (a) Yes (b) No
35. 35.🔁 What must there be for a current to flow? (a) a broken path (b) a plastic gap (c) one loose end (d) a complete loop
36. 36.True or false: if a wire is cut, the circuit is open and no current flows. (a) True (b) False
37. 37.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
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 copper wire. Does the bulb glow? (a) Yes (b) No
39. 39.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
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 coin. Does the bulb glow? (a) Yes (b) No

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