Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 709 · 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.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
2. 2.True or false: if all wires are joined, the circuit is closed and current flows. (a) True (b) False
3. 3.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
4. 4.Which of these means the circuit is open? (a) the switch is OFF (b) the loop is complete (c) the switch is ON (d) all wires are joined
5. 5.Which of these means the circuit is open? (a) the loop is complete (b) the bulb is unscrewed (c) the switch is ON (d) all wires are joined
6. 6.🔁 What do we call a circuit with a break in it? (a) a series circuit (b) a full circuit (c) a closed circuit (d) an open circuit
7. 7.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
8. 8.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) none (b) both of them (c) only one (d) it does not matter
9. 9.Which of these means the circuit is closed? (a) a wire is cut (b) the switch is OFF (c) the bulb is unscrewed (d) the loop is complete
10. 10.🔦 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 metal paper clip. Does the bulb glow? (a) No (b) Yes
11. 11.True or false: if the switch is ON, the circuit is closed and current flows. (a) False (b) True
12. 12.🔦 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
13. 13.True or false: if the switch is ON, the circuit is open and no current flows. (a) False (b) True
14. 14.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
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 glass marble. Does the bulb glow? (a) No (b) Yes
16. 16.🔦 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
17. 17.🔦 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
18. 18.Which of these means the circuit is closed? (a) a wire has come loose (b) the bulb is unscrewed (c) a wire is cut (d) all wires are joined
19. 19.🔁 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
20. 20.True or false: if a wire has come loose, the circuit is open and no current flows. (a) False (b) True
21. 21.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
22. 22.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the base (b) the filament (c) the switch (d) the glass
23. 23.🔦 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) Yes (b) No
24. 24.🔦 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 paper strip. Does the bulb glow? (a) No (b) Yes
25. 25.🔦 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
26. 26.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
27. 27.🔦 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
28. 28.True or false: if a wire is cut, the circuit is closed and current flows. (a) False (b) True
29. 29.🔦 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 ruler. Does the bulb glow? (a) Yes (b) No
30. 30.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
31. 31.🔦 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 woollen thread. Does the bulb glow? (a) No (b) Yes
32. 32.True or false: if all wires are joined, the circuit is open and no current flows. (a) False (b) True
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 copper wire. Does the bulb glow? (a) Yes (b) No
34. 34.Which of these means the circuit is closed? (a) a wire is cut (b) the bulb is unscrewed (c) the switch is OFF (d) the switch is ON
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. A gap in one wire is bridged by a ceramic cup. Does the bulb glow? (a) No (b) Yes
36. 36.True or false: if the bulb is unscrewed, the circuit is open and no current flows. (a) True (b) False
37. 37.True or false: if a cell is taken out, the circuit is open and no current flows. (a) False (b) True
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.🔦 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 graphite rod. Does the bulb glow? (a) Yes (b) No
40. 40.🔦 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 aluminium foil. Does the bulb glow? (a) Yes (b) No

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