Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 891 · 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 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 an iron nail. Does the bulb glow? (a) No (b) Yes
2. 2.🔦 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
3. 3.🔦 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
4. 4.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
5. 5.Which of these means the circuit is closed? (a) a wire has come loose (b) a cell is taken out (c) the switch is OFF (d) all wires are joined
6. 6.🔦 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) Yes (b) No
7. 7.🔁 What do we call a circuit with a break in it? (a) an open circuit (b) a closed circuit (c) a series circuit (d) a full circuit
8. 8.True or false: if the loop is complete, the circuit is closed and current flows. (a) False (b) True
9. 9.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) False (b) True
10. 10.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the base (b) the glass (c) the filament (d) the switch
11. 11.Which of these means the circuit is open? (a) the loop is complete (b) the switch is ON (c) a wire is cut (d) all wires are joined
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.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) a cell is taken out (c) the switch is ON (d) the switch is OFF
14. 14.🔦 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
15. 15.True or false: if all wires are joined, the circuit is open and no current flows. (a) False (b) True
16. 16.🔁 What must there be for a current to flow? (a) a complete loop (b) a plastic gap (c) a broken path (d) one loose end
17. 17.True or false: if all wires are joined, the circuit is closed and current flows. (a) True (b) False
18. 18.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
19. 19.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
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 safety pin. Does the bulb glow? (a) No (b) Yes
21. 21.🔦 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 graphite rod. Does the bulb glow? (a) Yes (b) No
22. 22.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 switch is OFF
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 cell is taken out? (a) open (b) closed
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 has come loose
26. 26.🔁 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) it does not matter (d) none
27. 27.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
28. 28.🔦 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 glass marble. Does the bulb glow? (a) No (b) Yes
29. 29.True or false: if the switch is OFF, the circuit is closed and current flows. (a) False (b) True
30. 30.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) False (b) True
31. 31.🔦 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 paper strip. Does the bulb glow? (a) No (b) Yes
32. 32.True or false: if a cell is taken out, the circuit is closed and current flows. (a) False (b) True
33. 33.🔦 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
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 ON. One wire has come loose from the cell. A gap in one wire is bridged by a steel spoon. Does the bulb glow? (a) No (b) Yes
36. 36.True or false: if the switch is OFF, the circuit is open and no current flows. (a) False (b) True
37. 37.Which of these means the circuit is closed? (a) the loop is complete (b) a wire is cut (c) the switch is OFF (d) a cell is taken out
38. 38.True or false: if the loop is complete, the circuit is open and no current flows. (a) False (b) True
39. 39.Which of these means the circuit is open? (a) the switch is ON (b) all wires are joined (c) the loop is complete (d) a cell is taken out
40. 40.🔦 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 graphite rod. Does the bulb glow? (a) No (b) Yes

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