Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 602 · 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.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the filament (c) the base (d) the switch
2. 2.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) it does not matter (b) none (c) both of them (d) only one
3. 3.True or false: if the loop is complete, the circuit is closed and current flows. (a) True (b) False
4. 4.🔦 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
5. 5.🔦 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
6. 6.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
7. 7.Which of these means the circuit is open? (a) all wires are joined (b) the loop is complete (c) the switch is ON (d) the switch is OFF
8. 8.🔦 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
9. 9.Which of these means the circuit is closed? (a) the switch is OFF (b) the loop is complete (c) a wire is cut (d) a wire has come loose
10. 10.True or false: if a cell is taken out, the circuit is open and no current flows. (a) False (b) True
11. 11.Which of these means the circuit is closed? (a) the switch is OFF (b) a wire has come loose (c) all wires are joined (d) a wire is cut
12. 12.True or false: if a wire has come loose, the circuit is closed and current flows. (a) True (b) False
13. 13.True or false: if all wires are joined, the circuit is closed and current flows. (a) True (b) False
14. 14.Which of these means the circuit is open? (a) the loop is complete (b) all wires are joined (c) a wire has come loose (d) the switch is ON
15. 15.🔁 What must there be for a current to flow? (a) a plastic gap (b) one loose end (c) a broken path (d) a complete loop
16. 16.🔦 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 wooden stick. Does the bulb glow? (a) No (b) Yes
17. 17.🔦 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 straw. Does the bulb glow? (a) No (b) Yes
18. 18.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
19. 19.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
20. 20.🔦 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 woollen thread. Does the bulb glow? (a) Yes (b) No
21. 21.Which of these means the circuit is open? (a) the switch is ON (b) all wires are joined (c) the bulb is unscrewed (d) the loop is complete
22. 22.🔁 Is the circuit closed or open if a wire has come loose? (a) open (b) closed
23. 23.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) False (b) True
24. 24.Which of these means the circuit is open? (a) the loop is complete (b) the switch is ON (c) a cell is taken out (d) all wires are joined
25. 25.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
26. 26.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
27. 27.🔦 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
28. 28.🔁 What do we call a circuit with a break in it? (a) a series circuit (b) a closed circuit (c) a full circuit (d) an open circuit
29. 29.True or false: if a cell is taken out, the circuit is closed and current flows. (a) True (b) False
30. 30.True or false: if the switch is OFF, the circuit is closed and current flows. (a) False (b) True
31. 31.True or false: if the loop is complete, the circuit is open and no current flows. (a) True (b) False
32. 32.True or false: if a wire is cut, the circuit is closed and current flows. (a) False (b) True
33. 33.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) True (b) False
34. 34.🔦 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
35. 35.🔦 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
36. 36.🔦 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 copper wire. Does the bulb glow? (a) Yes (b) No
37. 37.🔦 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 woollen thread. Does the bulb glow? (a) No (b) Yes
38. 38.🔦 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 glass marble. Does the bulb glow? (a) No (b) Yes
39. 39.🔦 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
40. 40.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) a wire has come loose (c) the switch is OFF (d) the switch is ON

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