Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 509 · 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 a cell is taken out? (a) open (b) closed
2. 2.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
3. 3.🔦 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
4. 4.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
5. 5.Which of these means the circuit is open? (a) the switch is ON (b) a cell is taken out (c) all wires are joined (d) the loop is complete
6. 6.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) only one (b) it does not matter (c) none (d) both of them
7. 7.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
8. 8.Which of these means the circuit is closed? (a) the switch is OFF (b) all wires are joined (c) the bulb is unscrewed (d) a wire is cut
9. 9.🔦 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
10. 10.True or false: if a cell is taken out, the circuit is open and no current flows. (a) True (b) False
11. 11.🔁 What must there be for a current to flow? (a) a plastic gap (b) a broken path (c) a complete loop (d) one loose end
12. 12.🔦 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 brass key. Does the bulb glow? (a) Yes (b) No
13. 13.🔦 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
14. 14.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
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 steel spoon. Does the bulb glow? (a) No (b) Yes
16. 16.Which of these means the circuit is closed? (a) a cell is taken out (b) a wire is cut (c) a wire has come loose (d) the loop is complete
17. 17.🔦 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) No (b) Yes
18. 18.True or false: if the switch is OFF, the circuit is closed and current flows. (a) False (b) True
19. 19.True or false: if the switch is ON, the circuit is closed and current flows. (a) True (b) False
20. 20.Which of these means the circuit is closed? (a) a cell is taken out (b) the bulb is unscrewed (c) the switch is ON (d) the switch is OFF
21. 21.True or false: if the loop is complete, the circuit is closed and current flows. (a) False (b) True
22. 22.True or false: if all wires are joined, the circuit is closed and current flows. (a) False (b) True
23. 23.🔦 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
24. 24.🔦 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
25. 25.Which of these means the circuit is open? (a) all wires are joined (b) the switch is ON (c) the loop is complete (d) a wire has come loose
26. 26.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
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) Yes (b) No
28. 28.🔦 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) No (b) Yes
29. 29.True or false: if a wire is cut, the circuit is closed and current flows. (a) False (b) True
30. 30.🔦 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 copper wire. Does the bulb glow? (a) No (b) Yes
31. 31.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) True (b) False
32. 32.Which of these means the circuit is open? (a) the loop is complete (b) a wire is cut (c) the switch is ON (d) all wires are joined
33. 33.Which of these means the circuit is open? (a) all wires are joined (b) the bulb is unscrewed (c) the switch is ON (d) the loop is complete
34. 34.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
35. 35.🔦 A circuit has a new cell, a good bulb and a switch that is OFF. All the wires are firmly joined. Does the bulb glow? (a) No (b) Yes
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 steel coin. Does the bulb glow? (a) No (b) Yes
37. 37.🔁 What do we call a circuit with a break in it? (a) a closed circuit (b) a series circuit (c) a full circuit (d) an open circuit
38. 38.True or false: if a wire is cut, the circuit is open and no current flows. (a) True (b) False
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 wooden stick. Does the bulb glow? (a) Yes (b) No
40. 40.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the base (b) the switch (c) the filament (d) the glass

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