Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 839 · 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.🔁 What must there be for a current to flow? (a) a complete loop (b) one loose end (c) a plastic gap (d) a broken path
2. 2.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
3. 3.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
4. 4.🔦 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
5. 5.Which of these means the circuit is open? (a) all wires are joined (b) the loop is complete (c) the switch is ON (d) a cell is taken out
6. 6.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
7. 7.True or false: if the loop is complete, the circuit is open and no current flows. (a) True (b) False
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 graphite rod. Does the bulb glow? (a) No (b) Yes
9. 9.True or false: if a wire is cut, the circuit is closed and current flows. (a) True (b) False
10. 10.🔦 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 dry cork. Does the bulb glow? (a) Yes (b) No
11. 11.True or false: if a wire has come loose, the circuit is open and no current flows. (a) False (b) True
12. 12.Which of these means the circuit is open? (a) a wire has come loose (b) all wires are joined (c) the switch is ON (d) the loop is complete
13. 13.🔁 What do we call a circuit with a break in it? (a) a full circuit (b) a series circuit (c) a closed circuit (d) an open circuit
14. 14.Which of these means the circuit is closed? (a) the switch is OFF (b) a wire has come loose (c) the switch is ON (d) a cell is taken out
15. 15.🔁 Is the circuit closed or open if a wire is cut? (a) open (b) closed
16. 16.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) none (b) it does not matter (c) both of them (d) only one
17. 17.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
18. 18.True or false: if the switch is OFF, the circuit is closed and current flows. (a) True (b) False
19. 19.True or false: if a cell is taken out, the circuit is open and no current flows. (a) False (b) True
20. 20.True or false: if all wires are joined, the circuit is closed and current flows. (a) True (b) False
21. 21.🔦 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
22. 22.🔦 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 metal paper clip. Does the bulb glow? (a) Yes (b) No
23. 23.🔦 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 rubber band. Does the bulb glow? (a) No (b) Yes
24. 24.Which of these means the circuit is closed? (a) a cell is taken out (b) all wires are joined (c) a wire has come loose (d) the switch is OFF
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. A gap in one wire is bridged by an iron nail. Does the bulb glow? (a) Yes (b) No
26. 26.🔦 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 graphite rod. Does the bulb glow? (a) No (b) Yes
27. 27.True or false: if a wire has come loose, the circuit is closed and current flows. (a) True (b) False
28. 28.🔦 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
29. 29.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
30. 30.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
31. 31.🔦 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 wooden stick. Does the bulb glow? (a) No (b) Yes
32. 32.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) True (b) False
33. 33.🔦 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) No (b) Yes
34. 34.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the switch (c) the filament (d) the base
35. 35.True or false: if the loop is complete, the circuit is closed and current flows. (a) False (b) True
36. 36.Which of these means the circuit is closed? (a) a cell is taken out (b) the bulb is unscrewed (c) the loop is complete (d) a wire has come loose
37. 37.Which of these means the circuit is open? (a) all wires are joined (b) the bulb is unscrewed (c) the loop is complete (d) the switch is ON
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 steel spoon. Does the bulb glow? (a) No (b) Yes
39. 39.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
40. 40.True or false: if a wire is cut, the circuit is open and no current flows. (a) True (b) False

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