Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 796 · 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.Which of these means the circuit is closed? (a) the loop is complete (b) the switch is OFF (c) the bulb is unscrewed (d) a wire is cut
2. 2.Which of these means the circuit is open? (a) the loop is complete (b) all wires are joined (c) the switch is ON (d) a wire is cut
3. 3.🔦 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 wooden stick. Does the bulb glow? (a) Yes (b) No
4. 4.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the filament (b) the glass (c) the base (d) the switch
5. 5.Which of these means the circuit is closed? (a) all wires are joined (b) a wire has come loose (c) the bulb is unscrewed (d) a wire is cut
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.Which of these means the circuit is open? (a) the switch is ON (b) the loop is complete (c) all wires are joined (d) a wire has come loose
8. 8.🔁 What must there be for a current to flow? (a) a broken path (b) one loose end (c) a complete loop (d) a plastic gap
9. 9.True or false: if a cell is taken out, the circuit is open and no current flows. (a) False (b) True
10. 10.True or false: if all wires are joined, the circuit is closed and current flows. (a) True (b) False
11. 11.🔦 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 plastic straw. Does the bulb glow? (a) No (b) Yes
12. 12.🔦 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
13. 13.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) the switch is ON (c) a wire has come loose (d) a cell is taken out
14. 14.True or false: if the switch is ON, the circuit is open and no current flows. (a) False (b) True
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. A gap in one wire is bridged by a steel spoon. Does the bulb glow? (a) No (b) Yes
16. 16.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
17. 17.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) False (b) True
18. 18.Which of these means the circuit is open? (a) a cell is taken out (b) the loop is complete (c) the switch is ON (d) all wires are joined
19. 19.🔦 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 copper wire. Does the bulb glow? (a) No (b) Yes
20. 20.🔦 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
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 dry cork. Does the bulb glow? (a) Yes (b) No
22. 22.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
23. 23.True or false: if a wire has come loose, the circuit is closed and current flows. (a) True (b) False
24. 24.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
25. 25.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
26. 26.Which of these means the circuit is open? (a) the loop is complete (b) the switch is OFF (c) all wires are joined (d) the switch is ON
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 metal paper clip. Does the bulb glow? (a) No (b) Yes
28. 28.True or false: if a cell is taken out, the circuit is closed and current flows. (a) True (b) False
29. 29.🔦 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) No (b) Yes
30. 30.True or false: if all wires are joined, the circuit is open and no current flows. (a) True (b) False
31. 31.True or false: if the switch is ON, the circuit is closed and current flows. (a) False (b) True
32. 32.True or false: if the switch is OFF, the circuit is open and no current flows. (a) False (b) True
33. 33.🔁 What do we call a circuit with a break in it? (a) a full circuit (b) an open circuit (c) a closed circuit (d) a series circuit
34. 34.🔦 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 glass marble. Does the bulb glow? (a) No (b) Yes
35. 35.🔦 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 wooden stick. Does the bulb glow? (a) No (b) Yes
36. 36.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
37. 37.🔦 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
38. 38.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
39. 39.Which of these means the circuit is open? (a) the loop is complete (b) all wires are joined (c) the switch is ON (d) the bulb is unscrewed
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 aluminium foil. Does the bulb glow? (a) Yes (b) No

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