Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 242 · 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.True or false: if a cell is taken out, the circuit is open and no current flows. (a) False (b) True
2. 2.True or false: if the switch is OFF, the circuit is closed and current flows. (a) False (b) True
3. 3.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
4. 4.🔁 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
5. 5.🔦 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) Yes (b) No
6. 6.🔦 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
7. 7.True or false: if the loop is complete, the circuit is closed and current flows. (a) False (b) True
8. 8.Which of these means the circuit is closed? (a) a wire is cut (b) the bulb is unscrewed (c) the switch is ON (d) a cell is taken out
9. 9.🔦 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
10. 10.🔦 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
11. 11.🔦 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 cotton thread. Does the bulb glow? (a) Yes (b) No
12. 12.True or false: if the switch is ON, the circuit is open and no current flows. (a) True (b) False
13. 13.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the base (b) the filament (c) the switch (d) the glass
14. 14.True or false: if a wire is cut, the circuit is open and no current flows. (a) False (b) True
15. 15.🔦 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 spoon. Does the bulb glow? (a) No (b) Yes
16. 16.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) only one (b) none (c) both of them (d) it does not matter
17. 17.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
18. 18.True or false: if all wires are joined, the circuit is open and no current flows. (a) True (b) False
19. 19.Which of these means the circuit is open? (a) the switch is ON (b) all wires are joined (c) the loop is complete (d) the bulb is unscrewed
20. 20.🔦 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) Yes (b) No
21. 21.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) False (b) True
22. 22.🔦 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) Yes (b) No
23. 23.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
24. 24.🔦 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 cotton thread. Does the bulb glow? (a) Yes (b) No
25. 25.🔦 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
26. 26.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
27. 27.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
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 steel coin. Does the bulb glow? (a) Yes (b) No
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 aluminium foil. Does the bulb glow? (a) Yes (b) No
30. 30.🔁 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
31. 31.🔦 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 band. Does the bulb glow? (a) Yes (b) No
32. 32.🔦 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
33. 33.Which of these means the circuit is closed? (a) a wire is cut (b) a wire has come loose (c) the loop is complete (d) a cell is taken out
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 dry cork. Does the bulb glow? (a) No (b) Yes
35. 35.True or false: if the switch is OFF, the circuit is open and no current flows. (a) True (b) False
36. 36.True or false: if the loop is complete, the circuit is open and no current flows. (a) True (b) False
37. 37.Which of these means the circuit is closed? (a) a wire has come loose (b) the switch is OFF (c) all wires are joined (d) the bulb is unscrewed
38. 38.🔦 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 an iron nail. Does the bulb glow? (a) Yes (b) No
39. 39.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) True (b) False
40. 40.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed

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