Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 863 · 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.Which job needs a temperature sensor? (a) measure classroom noise (b) keep an incubator warm (c) warn of a gas leak (d) switch on with a clap
2. 2.🔺 A current of 1 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
3. 3.🤖 if (temperature > 30) { show “Hot” } else if (temperature > 18) { show “Warm” } else { show “Cool” }
   The temperature is 22 °C. What is shown? (a) Hot (b) Warm (c) Cool
4. 4.Which job needs an LED? (a) move water to plants (b) spin a robot’s wheels (c) show the temperature (d) show a status light
5. 5.⚡ Which formula gives electric power? (a) P = V ÷ I (b) P = I ÷ V (c) P = V + I (d) P = V × I
6. 6.💡 An LED (with its resistor) is on pin 7. All pins start LOW. The program runs once:
   set pin 7 HIGH
   set pin 8 LOW
   set pin 8 HIGH
   Is the LED ON or OFF at the end? (a) OFF (b) ON
7. 7.Which of these is true of a series circuit? (a) each gets the full volts (b) one out, the rest glow (c) one bulb out, all go out (d) used in house wiring
8. 8.What does a tilt switch do? (a) stays where you flip it (b) flips up or down (c) closes when tipped over (d) slides side to side
9. 9.⏱️ repeat 2 times { buzzer ON; wait 900 ms; buzzer OFF; wait 700 ms }
   How many milliseconds does this take in all?
10. 10.Which drawing is the symbol for an ammeter? (a) a circle with A inside (b) a line lifted at a gap (c) two or more cell symbols (d) one tall, one short bar
11. 11.⚡ What does an electric iron mainly change electricity into? (a) light (b) movement (c) heat (d) sound
12. 12.True or false: a circle with V inside is the symbol for a cell. (a) True (b) False
13. 13.🔺 In the V-I-R triangle, how do we find V? (a) V = I ÷ R (b) V = I + R (c) V = R ÷ I (d) V = I × R
14. 14.🧮 A 33 Ω resistor is joined in series with two equal 20 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
15. 15.Which of these means the circuit is closed? (a) a wire is cut (b) a cell is taken out (c) the switch is OFF (d) the loop is complete
16. 16.Which drawing is the symbol for a motor? (a) triangle, bar and arrows (b) a circle with a cross (c) a long and a short line (d) a circle with M inside
17. 17.🔦 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 steel coin. Does the bulb glow? (a) Yes (b) No
18. 18.Which of these is true of a series circuit? (a) one out, the rest glow (b) used in house wiring (c) each gets the full volts (d) bulbs share the voltage
19. 19.🌈 In the resistor colour code, which number does brown stand for?
20. 20.Which of these is the process? (a) a buzzer beeps (b) a light level reading (c) a soil moisture reading (d) check if temp > 30
21. 21.🔁 What does a variable do in a program? (a) measures light (b) stores a value (c) blinks an LED (d) joins two wires
22. 22.True or false: to touch a switch when wet is safe. (a) False (b) True
23. 23.True or false: “one out, the rest glow” is true of a series circuit. (a) False (b) True
24. 24.💡 A red LED (it uses 2 V) is joined with a 150 Ω resistor to a 3.5 V supply. What current flows (in mA)?
25. 25.🔌 Is an iron nail a conductor or an insulator? (a) an insulator (b) a conductor
26. 26.🔁 count = 0
    while (count < 28) { count = count + 4 }
    How many times does the loop run?
27. 27.🔋 On a cell, does “the end with a bump” mean the + end or the − end? (a) − (negative) (b) + (positive)
28. 28.🧮 Three equal 15 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
29. 29.🔺 A current of 40 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
30. 30.⏱️ loop forever { LED ON; wait 200 ms; LED OFF; wait 50 ms }
    How many times does the LED blink in 8 seconds?
31. 31.⚠️ Why must we never touch switches with wet hands? (a) water makes it cold (b) water carries current (c) it spoils the paint (d) it is just untidy
32. 32.🔋 Does a solar panel give electricity or use electricity? (a) uses electricity (b) gives electricity
33. 33.Which of these is safe? (a) stop if a part gets hot (b) poke things in a socket (c) touch a switch when wet (d) use a cable with cuts
34. 34.🔗 Series or parallel circuit: “used in house wiring”? (a) series (b) parallel
35. 35.🤖 if (temperature > 25) { fan ON } else { fan OFF }
    The temperature sensor reads 27 °C. What happens? (a) fan ON (b) fan OFF
36. 36.🧮 Two equal 100 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
37. 37.🔺 A current of 25 mA flows when 10 V is joined across a resistor. What is its resistance (in ohms)?
38. 38.🔢 To run one loop of a plant-watering program, what comes right after “compare with the limit”? (a) wait a few seconds (b) switch the pump on/off (c) read the soil sensor
39. 39.True or false: “how bright a room is” is an analog signal. (a) False (b) True
40. 40.💡 Why is house wiring done in parallel? (a) to save copper only (b) so all go off together (c) each gets full voltage (d) to make bulbs dim

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