Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 380 · 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) only one (b) both of them (c) none (d) it does not matter
2. 2.🔦 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
3. 3.🔁 What do we call a circuit with a break in it? (a) a closed circuit (b) an open circuit (c) a full circuit (d) a series circuit
4. 4.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
5. 5.True or false: if the switch is ON, the circuit is open and no current flows. (a) False (b) True
6. 6.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
7. 7.True or false: if a wire has come loose, the circuit is closed and 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 an iron nail. Does the bulb glow? (a) No (b) Yes
9. 9.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
10. 10.Which of these means the circuit is closed? (a) a wire has come loose (b) the bulb is unscrewed (c) the switch is OFF (d) all wires are joined
11. 11.🔁 What must there be for a current to flow? (a) a broken path (b) a plastic gap (c) a complete loop (d) one loose end
12. 12.🔦 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
13. 13.🔦 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 copper wire. Does the bulb glow? (a) Yes (b) No
14. 14.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
15. 15.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) False (b) True
16. 16.🔦 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) No (b) Yes
17. 17.True or false: if the switch is ON, the circuit is closed and current flows. (a) True (b) False
18. 18.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
19. 19.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
20. 20.🔦 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
21. 21.Which of these means the circuit is closed? (a) the switch is ON (b) the switch is OFF (c) a cell is taken out (d) a wire is cut
22. 22.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the switch (b) the filament (c) the base (d) the glass
23. 23.Which of these means the circuit is closed? (a) the switch is OFF (b) a wire is cut (c) a cell is taken out (d) the loop is complete
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 a steel spoon. Does the bulb glow? (a) No (b) Yes
25. 25.🔦 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) No (b) Yes
26. 26.True or false: if a cell is taken out, 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 ceramic cup. Does the bulb glow? (a) No (b) Yes
28. 28.Which of these means the circuit is open? (a) all wires are joined (b) the loop is complete (c) a wire has come loose (d) the switch is ON
29. 29.True or false: if a wire is cut, the circuit is closed and current flows. (a) True (b) False
30. 30.True or false: if the switch is OFF, the circuit is closed and current flows. (a) True (b) False
31. 31.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
32. 32.True or false: if all wires are joined, the circuit is open and no current flows. (a) True (b) False
33. 33.🔦 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
34. 34.True or false: if all wires are joined, the circuit is closed and current flows. (a) True (b) False
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 aluminium foil. Does the bulb glow? (a) Yes (b) No
36. 36.🔦 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 band. Does the bulb glow? (a) Yes (b) No
37. 37.🔦 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
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 rubber band. Does the bulb glow? (a) No (b) Yes
39. 39.🔦 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 dry cork. Does the bulb glow? (a) Yes (b) No
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 safety pin. Does the bulb glow? (a) Yes (b) No

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