Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 639 · 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.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
2. 2.True or false: if the loop is complete, the circuit is open and no current flows. (a) False (b) True
3. 3.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
4. 4.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) it does not matter (b) only one (c) none (d) both of them
5. 5.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
6. 6.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the switch (c) the filament (d) the base
7. 7.True or false: if the bulb is unscrewed, 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 brass key. Does the bulb glow? (a) Yes (b) No
9. 9.Which of these means the circuit is open? (a) the switch is OFF (b) the switch is ON (c) all wires are joined (d) the loop is complete
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 rubber band. Does the bulb glow? (a) Yes (b) No
11. 11.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
12. 12.Which of these means the circuit is closed? (a) a wire is cut (b) the bulb is unscrewed (c) a wire has come loose (d) all wires are joined
13. 13.True or false: if the switch is OFF, the circuit is open and no current flows. (a) True (b) False
14. 14.🔦 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 plastic straw. Does the bulb glow? (a) Yes (b) No
15. 15.🔦 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) Yes (b) No
16. 16.🔁 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
17. 17.🔦 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
18. 18.🔦 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 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 a cotton thread. Does the bulb glow? (a) No (b) Yes
20. 20.🔦 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
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 cotton thread. Does the bulb glow? (a) No (b) Yes
22. 22.True or false: if a wire is cut, the circuit is open and no current flows. (a) True (b) False
23. 23.True or false: if a wire has come loose, the circuit is open and no current flows. (a) False (b) True
24. 24.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
25. 25.🔦 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
26. 26.🔦 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
27. 27.🔁 What must there be for a current to flow? (a) a complete loop (b) a broken path (c) one loose end (d) a plastic gap
28. 28.True or false: if the switch is ON, the circuit is open and no current flows. (a) False (b) True
29. 29.Which of these means the circuit is closed? (a) the switch is OFF (b) a wire has come loose (c) the loop is complete (d) a cell is taken out
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 rubber eraser. Does the bulb glow? (a) No (b) Yes
31. 31.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
32. 32.True or false: if the switch is ON, the circuit is closed and current flows. (a) True (b) False
33. 33.Which of these means the circuit is closed? (a) a wire is cut (b) the switch is ON (c) a wire has come loose (d) the switch is OFF
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. Does the bulb glow? (a) Yes (b) No
35. 35.🔦 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 an iron nail. Does the bulb glow? (a) Yes (b) No
36. 36.🔦 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 aluminium foil. Does the bulb glow? (a) No (b) Yes
37. 37.Which of these means the circuit is open? (a) the switch is ON (b) the loop is complete (c) a wire is cut (d) all wires are joined
38. 38.True or false: if a wire has come loose, the circuit is closed and current flows. (a) False (b) True
39. 39.True or false: if a cell is taken out, the circuit is open and no current flows. (a) False (b) True
40. 40.🔦 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) Yes (b) No

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