Electronics Worksheet: Simple Circuit – Open and Closed

Electronics lesson 4: Open and closed circuits · Set 434 · 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 the switch is ON, the circuit is open and no current flows. (a) False (b) True
2. 2.True or false: if the loop is complete, the circuit is open and no current flows. (a) False (b) True
3. 3.Which of these means the circuit is open? (a) the switch is ON (b) the switch is OFF (c) the loop is complete (d) all wires are joined
4. 4.🔦 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 metal paper clip. Does the bulb glow? (a) Yes (b) No
5. 5.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
6. 6.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) only one (b) none (c) it does not matter (d) both of them
7. 7.🔦 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
8. 8.True or false: if a cell is taken out, the circuit is closed and current flows. (a) False (b) True
9. 9.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the switch (b) the base (c) the filament (d) the glass
10. 10.Which of these means the circuit is open? (a) the switch is ON (b) the loop is complete (c) a wire has come loose (d) all wires are joined
11. 11.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed
12. 12.🔁 What do we call a circuit with a break in it? (a) a closed circuit (b) an open circuit (c) a series circuit (d) a full circuit
13. 13.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
14. 14.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
15. 15.Which of these means the circuit is open? (a) all wires are joined (b) a wire is cut (c) the loop is complete (d) the switch is ON
16. 16.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
17. 17.True or false: if all wires are joined, the circuit is open and no 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.Which of these means the circuit is open? (a) the loop is complete (b) all wires are joined (c) the switch is ON (d) a cell is taken out
20. 20.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
21. 21.🔦 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 dry cork. Does the bulb glow? (a) Yes (b) No
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. Does the bulb glow? (a) No (b) Yes
23. 23.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 cell is taken out
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 graphite rod. Does the bulb glow? (a) Yes (b) No
25. 25.🔁 What must there be for a current to flow? (a) one loose end (b) a plastic gap (c) a complete loop (d) a broken path
26. 26.🔦 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
27. 27.🔦 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) Yes (b) No
28. 28.🔦 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
29. 29.True or false: if the switch is ON, the circuit is closed and current flows. (a) True (b) False
30. 30.🔦 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 aluminium foil. Does the bulb glow? (a) Yes (b) No
31. 31.True or false: if the bulb is unscrewed, the circuit is closed and current flows. (a) True (b) False
32. 32.🔦 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 plastic straw. Does the bulb glow? (a) Yes (b) No
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 wooden stick. Does the bulb glow? (a) Yes (b) No
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. A gap in one wire is bridged by a copper wire. Does the bulb glow? (a) Yes (b) No
35. 35.🔦 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
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 an iron nail. Does the bulb glow? (a) No (b) Yes
37. 37.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
38. 38.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
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 cotton thread. Does the bulb glow? (a) No (b) Yes
40. 40.Which of these means the circuit is open? (a) the loop is complete (b) the switch is ON (c) all wires are joined (d) the bulb is unscrewed

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