Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 71 · 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 open? (a) all wires are joined (b) a cell is taken out (c) the switch is ON (d) the loop is complete
2. 2.True or false: if a wire has come loose, the circuit is open and no current flows. (a) True (b) False
3. 3.🔦 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 plastic straw. Does the bulb glow? (a) Yes (b) No
4. 4.🔦 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
5. 5.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 cell is taken out
6. 6.Which of these means the circuit is open? (a) the switch is ON (b) a wire is cut (c) all wires are joined (d) the loop is complete
7. 7.🔦 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
8. 8.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the filament (b) the switch (c) the base (d) the glass
9. 9.Which of these means the circuit is closed? (a) a wire has come loose (b) the switch is OFF (c) a wire is cut (d) the loop is complete
10. 10.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
11. 11.🔁 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
12. 12.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
13. 13.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
14. 14.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) False (b) True
15. 15.🔁 Is the circuit closed or open if a wire is cut? (a) open (b) closed
16. 16.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
17. 17.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) none (b) both of them (c) it does not matter (d) only one
18. 18.True or false: if a wire is cut, the circuit is closed and current flows. (a) False (b) True
19. 19.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) a wire has come loose (c) the switch is ON (d) the switch is OFF
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. A gap in one wire is bridged by a cotton thread. 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. 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
22. 22.True or false: if a wire has come loose, the circuit is closed and current flows. (a) False (b) True
23. 23.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
24. 24.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) True (b) False
25. 25.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
26. 26.🔦 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
27. 27.True or false: if the switch is ON, the circuit is open and no current flows. (a) False (b) True
28. 28.True or false: if a wire is cut, the circuit is open and no current flows. (a) True (b) False
29. 29.🔦 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
30. 30.🔦 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 eraser. Does the bulb glow? (a) No (b) Yes
31. 31.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
32. 32.🔦 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
33. 33.True or false: if the loop is complete, the circuit is open and no current flows. (a) True (b) False
34. 34.🔁 What must there be for a current to flow? (a) one loose end (b) a plastic gap (c) a broken path (d) a complete loop
35. 35.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
36. 36.True or false: if a cell is taken out, the circuit is open and no current flows. (a) True (b) False
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) No (b) Yes
38. 38.🔦 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 metal paper clip. Does the bulb glow? (a) No (b) Yes
39. 39.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
40. 40.True or false: if all wires are joined, the circuit is open and no current flows. (a) True (b) False

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