Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 712 · 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 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
2. 2.True or false: if a wire is cut, 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 ON. All the wires are firmly joined. Does the bulb glow? (a) No (b) Yes
4. 4.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
5. 5.True or false: if a wire has come loose, the circuit is closed and current flows. (a) True (b) False
6. 6.Which of these means the circuit is open? (a) a cell is taken out (b) all wires are joined (c) the switch is ON (d) the loop is complete
7. 7.Which of these means the circuit is open? (a) a wire has come loose (b) the switch is ON (c) all wires are joined (d) the loop is complete
8. 8.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
9. 9.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) False (b) True
10. 10.🔁 What do we call a circuit with a break in it? (a) a closed circuit (b) a series circuit (c) an open circuit (d) a full circuit
11. 11.🔁 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
12. 12.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
13. 13.🔦 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
14. 14.🔦 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 ceramic cup. Does the bulb glow? (a) No (b) Yes
15. 15.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the filament (b) the switch (c) the base (d) the glass
16. 16.Which of these means the circuit is closed? (a) a cell is taken out (b) the loop is complete (c) the switch is OFF (d) the bulb is unscrewed
17. 17.True or false: if the loop is complete, the circuit is closed and current flows. (a) True (b) False
18. 18.True or false: if a wire has come loose, the circuit is open and no current flows. (a) True (b) False
19. 19.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
20. 20.🔦 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 cotton thread. Does the bulb glow? (a) Yes (b) No
21. 21.True or false: if all wires are joined, the circuit is closed and current flows. (a) False (b) True
22. 22.True or false: if a cell is taken out, the circuit is closed and current flows. (a) False (b) True
23. 23.Which of these means the circuit is open? (a) the loop is complete (b) all wires are joined (c) the bulb is unscrewed (d) the switch is ON
24. 24.🔦 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 brass key. Does the bulb glow? (a) No (b) Yes
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. A gap in one wire is bridged by a copper wire. Does the bulb glow? (a) Yes (b) No
26. 26.Which of these means the circuit is open? (a) a wire is cut (b) the switch is ON (c) the loop is complete (d) all wires are joined
27. 27.Which of these means the circuit is closed? (a) all wires are joined (b) the switch is OFF (c) a cell is taken out (d) a wire has come loose
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 plastic ruler. Does the bulb glow? (a) No (b) Yes
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. Does the bulb glow? (a) No (b) Yes
30. 30.True or false: if the switch is ON, the circuit is closed and current flows. (a) True (b) False
31. 31.Which of these means the circuit is closed? (a) the switch is ON (b) a cell is taken out (c) the bulb is unscrewed (d) a wire is cut
32. 32.🔦 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 brass key. Does the bulb glow? (a) Yes (b) No
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 a wooden stick. Does the bulb glow? (a) No (b) Yes
34. 34.True or false: if the switch is OFF, the circuit is closed and current flows. (a) True (b) False
35. 35.True or false: if the switch is OFF, the circuit is open and no current flows. (a) True (b) False
36. 36.Which of these means the circuit is open? (a) all wires are joined (b) the switch is OFF (c) the loop is complete (d) the switch is ON
37. 37.🔦 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
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 a glass marble. Does the bulb glow? (a) Yes (b) No
39. 39.True or false: if all wires are joined, the circuit is open and no current flows. (a) False (b) True
40. 40.True or false: if the switch is ON, the circuit is open and no current flows. (a) False (b) True

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