Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 287 · 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.🔁 What must there be for a current to flow? (a) one loose end (b) a complete loop (c) a plastic gap (d) a broken path
2. 2.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
3. 3.🔁 What do we call a circuit with a break in it? (a) an open circuit (b) a full circuit (c) a closed circuit (d) a series circuit
4. 4.Which of these means the circuit is closed? (a) a wire is cut (b) all wires are joined (c) the switch is OFF (d) a cell is taken out
5. 5.Which of these means the circuit is open? (a) the switch is OFF (b) all wires are joined (c) the loop is complete (d) the switch is ON
6. 6.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the base (b) the filament (c) the switch (d) the glass
7. 7.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
8. 8.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
9. 9.Which of these means the circuit is open? (a) all wires are joined (b) the loop is complete (c) the bulb is unscrewed (d) the switch is ON
10. 10.🔦 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
11. 11.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) it does not matter (b) only one (c) both of them (d) none
12. 12.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 cell is taken out
13. 13.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) the switch is OFF (c) a wire has come loose (d) the switch is ON
14. 14.🔦 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
15. 15.True or false: if the loop is complete, the circuit is closed and current flows. (a) True (b) False
16. 16.True or false: if all wires are joined, the circuit is open and no current flows. (a) True (b) False
17. 17.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
18. 18.🔦 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 ruler. Does the bulb glow? (a) Yes (b) No
19. 19.True or false: if the switch is OFF, the circuit is closed and current flows. (a) True (b) False
20. 20.🔦 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
21. 21.True or false: if a wire has come loose, the circuit is open and no current flows. (a) True (b) False
22. 22.🔦 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 paper strip. Does the bulb glow? (a) Yes (b) No
23. 23.True or false: if a cell is taken out, the circuit is open and no current flows. (a) True (b) False
24. 24.True or false: if the switch is ON, the circuit is closed and current flows. (a) True (b) False
25. 25.🔦 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
26. 26.Which of these means the circuit is closed? (a) a cell is taken out (b) a wire is cut (c) the loop is complete (d) the bulb is unscrewed
27. 27.True or false: if a wire is cut, the circuit is closed and current flows. (a) False (b) True
28. 28.🔁 Is the circuit closed or open if a wire is cut? (a) open (b) closed
29. 29.True or false: if all wires are joined, the circuit is closed and current flows. (a) False (b) True
30. 30.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
31. 31.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
32. 32.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
33. 33.🔦 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) No (b) Yes
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 steel coin. Does the bulb glow? (a) No (b) Yes
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. Does the bulb glow? (a) No (b) Yes
36. 36.Which of these means the circuit is open? (a) the loop is complete (b) the switch is ON (c) a wire has come loose (d) all wires are joined
37. 37.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) True (b) False
38. 38.True or false: if a wire is cut, the circuit is open and no current flows. (a) True (b) False
39. 39.True or false: if a cell is taken out, the circuit is closed and current flows. (a) True (b) False
40. 40.🔦 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

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