Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 863 · 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 switch is ON? (a) open (b) closed
2. 2.🔁 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
3. 3.🔁 What must there be for a current to flow? (a) a broken path (b) one loose end (c) a plastic gap (d) a complete loop
4. 4.🔦 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
5. 5.🔦 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 aluminium foil. Does the bulb glow? (a) No (b) Yes
6. 6.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
7. 7.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
8. 8.True or false: if a wire has come loose, the circuit is open and no current flows. (a) True (b) False
9. 9.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
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 brass key. Does the bulb glow? (a) Yes (b) No
11. 11.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the base (c) the switch (d) the filament
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 paper strip. Does the bulb glow? (a) Yes (b) No
13. 13.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
14. 14.True or false: if the switch is OFF, the circuit is open and no current flows. (a) True (b) False
15. 15.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
16. 16.🔁 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
17. 17.🔦 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) Yes (b) No
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 a safety pin. Does the bulb glow? (a) No (b) Yes
19. 19.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
20. 20.True or false: if the switch is ON, the circuit is open and no current flows. (a) True (b) False
21. 21.True or false: if a cell is taken out, the circuit is open and no current flows. (a) False (b) True
22. 22.True or false: if a wire has come loose, the circuit is closed and current flows. (a) False (b) True
23. 23.🔦 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 an iron nail. Does the bulb glow? (a) No (b) Yes
24. 24.True or false: if a wire is cut, the circuit is closed and current flows. (a) False (b) True
25. 25.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 wire is cut
26. 26.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) the switch is OFF (c) a cell is taken out (d) all wires are joined
27. 27.True or false: if the loop is complete, the circuit is closed and current flows. (a) True (b) False
28. 28.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
29. 29.🔦 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 metal paper clip. Does the bulb glow? (a) Yes (b) No
30. 30.Which of these means the circuit is open? (a) all wires are joined (b) the loop is complete (c) a cell is taken out (d) the switch is ON
31. 31.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) True (b) False
32. 32.🔦 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 copper wire. Does the bulb glow? (a) Yes (b) No
33. 33.True or false: if all wires are joined, the circuit is open and no current flows. (a) True (b) False
34. 34.🔦 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 straw. Does the bulb glow? (a) No (b) Yes
35. 35.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
36. 36.Which of these means the circuit is closed? (a) the loop is complete (b) the bulb is unscrewed (c) a cell is taken out (d) a wire has come loose
37. 37.🔦 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 rubber band. 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 aluminium foil. Does the bulb glow? (a) Yes (b) No
39. 39.True or false: if the switch is OFF, the circuit is closed and current flows. (a) True (b) False
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 ceramic cup. Does the bulb glow? (a) No (b) Yes

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