Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 679 · 40 questions

Remember (Find the topic, use the idea): Find the topic: circuit, safety, formula, component, program, sensor or IoT. Use that lesson’s rule — complete loop, V = I × R, P = V × I, last command wins, true → if part. Safety answers are always: low voltage, dry hands, an adult, never the mains.

1. 1.🔋 7 identical 1.5 V cells are joined in series, but one of them is put in the wrong way round. What is the total voltage now (in volts)? =
2. 2.🔺 A current of 3 A flows when 15 V is joined across a resistor. What is its resistance (in ohms)?
3. 3.⚠️ Why must we never touch switches with wet hands? (a) water carries current (b) water makes it cold (c) it spoils the paint (d) it is just untidy
4. 4.Which of these means the circuit is closed? (a) the bulb is unscrewed (b) the switch is OFF (c) a wire has come loose (d) the loop is complete
5. 5.🌈 A resistor has the colour bands white, brown, black. What is its value (in ohms)?
6. 6.🔁 What do we call a circuit with a break in it? (a) a series circuit (b) a closed circuit (c) an open circuit (d) a full circuit
7. 7.True or false: “a single current path” is true of a parallel circuit. (a) True (b) False
8. 8.💡 A battery lights 5 identical bulbs joined in parallel. One more identical bulb is added in parallel. How do the bulbs glow now? (a) the same (b) dimmer (c) brighter
9. 9.🔌 Is a rubber eraser a conductor or an insulator? (a) a conductor (b) an insulator
10. 10.💡 An LED (with its resistor) is on pin 7. All pins start LOW. The program runs once:
    set pin 7 LOW
    set pin 7 HIGH
    Is the LED ON or OFF at the end? (a) OFF (b) ON
11. 11.🔦 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
12. 12.🔦 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) Yes (b) No
13. 13.🔋 Cells joined + to − in a row (series) give … (a) no voltage (b) the same voltage (c) a smaller voltage (d) a bigger voltage
14. 14.💡 A battery lights 5 identical bulbs joined in series. One more identical bulb is added in series. How do the bulbs glow now? (a) brighter (b) the same (c) dimmer
15. 15.True or false: a reed switch closes near a magnet. (a) True (b) False
16. 16.🔘 Which kind of switch flips up or down? (a) a reed switch (b) a slide switch (c) a tilt switch (d) a toggle switch
17. 17.Which of these is an input? (a) a water pump (b) an LED (c) a speaker (d) a temperature sensor
18. 18.🔦 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
19. 19.💡 Does it save or waste electricity to leave the TV on standby? (a) saves electricity (b) wastes electricity
20. 20.🔘 What does a switch do in a circuit? (a) changes the voltage (b) makes electricity (c) stores current (d) opens or closes the loop
21. 21.🔘 A cell and a bulb are joined to 2 side-by-side paths with one switch on each path — A and B (parallel). A is OFF and B is OFF. Does the bulb glow? (a) No (b) Yes
22. 22.🔋 How many 2 V cells must be joined in series to give 6 V?
23. 23.True or false: to open a phone charger is safe. (a) False (b) True
24. 24.💡 2 identical bulbs are joined in series with a battery and a closed switch on the main wire. Bulb 1 is taken out of its holder. Does bulb 2 glow? (a) Yes (b) No
25. 25.Which drawing is the symbol for a capacitor? (a) two or more cell symbols (b) a circle with A inside (c) two equal parallel lines (d) triangle, bar and arrows
26. 26.Which of these is a conductor? (a) a wooden stick (b) a ceramic cup (c) a steel coin (d) a cotton thread
27. 27.🔁 total = 0
    for i = 1 to 6 { total = total + i }
    What is total at the end?
28. 28.💡 What does LED stand for? (a) low energy device (b) light-emitting diode (c) light energy dial (d) large electric dial
29. 29.Which of these is a risky habit? (a) share only needed data (b) set a strong password (c) set up with a parent (d) share camera links
30. 30.✏️ In a circuit diagram, wires are usually drawn as … (a) wavy lines (b) little stars (c) dotted circles (d) straight lines
31. 31.🔋 What is a battery? (a) a kind of bulb (b) a switch with a lid (c) two or more cells joined (d) one single wire
32. 32.🔺 A current of 3 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
33. 33.💡 3 identical bulbs are joined in series with a battery and a closed switch on the main wire. All the bulbs are in place. How many bulbs glow?
34. 34.Which job needs an LED? (a) show a status light (b) open a gate to 90° (c) move water to plants (d) spin a robot’s wheels
35. 35.⚠️ Someone is getting a shock and is still touching a wire. What should you do? (a) pour water on them (b) wait and watch (c) pull them by the hand (d) shout for an adult
36. 36.⏱️ repeat 8 times { buzzer ON; wait 200 ms; buzzer OFF; wait 600 ms }
    How many milliseconds does this take in all?
37. 37.🔺 A current of 40 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
38. 38.Which job needs a servo motor? (a) show a status light (b) show the temperature (c) move water to plants (d) open a gate to 90°
39. 39.✏️ In a circuit diagram, which part is drawn as two equal parallel lines? (a) cell (b) bulb (c) voltmeter (d) capacitor
40. 40.🔋 Does a mobile phone give electricity or use electricity? (a) gives electricity (b) uses electricity

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