Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 267 · 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.⏱️ loop forever { LED ON; wait 100 ms; LED OFF; wait 150 ms }
   How many times does the LED blink in 8 seconds?
2. 2.⚡ A home appliance on the 230 V mains takes 8 A. What is its power (in watts)?
3. 3.🔺 A current of 40 mA flows when 8.8 V is joined across a resistor. What is its resistance (in ohms)?
4. 4.🔋 On a cell, does “the flat end” mean the + end or the − end? (a) − (negative) (b) + (positive)
5. 5.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 20 Ω resistor? (a) red-black-black (b) orange-red-black (c) red-black-brown (d) orange-black-black
6. 6.Which of these is a conductor? (a) a rubber eraser (b) a paper strip (c) an iron nail (d) a woollen thread
7. 7.⚡ A 4.5 W device works on 1.5 V. What current does it take (in amperes)? =
8. 8.💡 In a parallel circuit, one bulb breaks. What happens to the others? (a) they all go out (b) they keep glowing (c) they get dimmer (d) they explode
9. 9.True or false: to ignore update messages is a risky habit. (a) True (b) False
10. 10.🌈 Which band is read first on a resistor? (a) the gold band (b) any band (c) the one nearest an end (d) the widest gap
11. 11.What does a motor do? (a) boosts a small signal (b) is a resistance knob (c) makes things spin (d) senses how hot it is
12. 12.🤖 if (temperature > 33) { show “Hot” } else if (temperature > 23) { show “Warm” } else { show “Cool” }
    The temperature is 16 °C. What is shown? (a) Cool (b) Warm (c) Hot
13. 13.🔢 To run one loop of a plant-watering program, which is the FIRST step? (a) wait a few seconds (b) compare with the limit (c) read the soil sensor (d) switch the pump on/off
14. 14.💡 An LED (with its resistor) is on pin 8. All pins start LOW. The program runs once:
    set pin 8 LOW
    set pin 7 LOW
    Is the LED ON or OFF at the end? (a) OFF (b) ON
15. 15.🤖 Does a bicycle bell usually have a microcontroller inside? (a) Yes (b) No
16. 16.📏 Which unit measures power? (a) ohm (Ω) (b) ampere (A) (c) volt (V) (d) watt (W)
17. 17.🔋 A 3 V battery and three 1.5 V cells are joined in series, all facing the same way. What is the total voltage (in volts)? =
18. 18.⏱️ How many milliseconds are in 1 second? (a) 100 (b) 10 (c) 60 (d) 1000
19. 19.🤖 if (temperature > 30) { show “Hot” } else if (temperature > 21) { show “Warm” } else { show “Cool” }
    The temperature is 19 °C. What is shown? (a) Warm (b) Cool (c) Hot
20. 20.🌈 A resistor has the colour bands green, green, black. What is its value (in ohms)?
21. 21.⚡ A home appliance on the 230 V mains takes 5 A. What is its power (in watts)?
22. 22.🔺 A current of 10 mA flows when 3.3 V is joined across a resistor. What is its resistance (in ohms)?
23. 23.🧩 Which component senses how bright it is? (a) resistor (b) buzzer (c) fuse (d) LDR
24. 24.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
25. 25.⚠️ Who should be with you when you build a circuit? (a) a trusted adult (b) a stranger online (c) a younger child (d) nobody
26. 26.What does a tilt switch do? (a) stays where you flip it (b) works only while pressed (c) springs back when let go (d) closes when tipped over
27. 27.⏱️ loop forever { LED ON; wait 350 ms; LED OFF; wait 150 ms }
    How many times does the LED blink in 8 seconds?
28. 28.What does a potentiometer do? (a) limits the current (b) senses how bright it is (c) senses how hot it is (d) is a resistance knob
29. 29.True or false: “a break stops every bulb” is true of a series circuit. (a) True (b) False
30. 30.⚡ Which formula gives electric power? (a) P = V ÷ I (b) P = V × I (c) P = I ÷ V (d) P = V + I
31. 31.🧮 A 1.4 V battery is joined to 12 Ω and 2 Ω resistors in series. What current flows (in amperes)? =
32. 32.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 76000 Ω resistor? (a) violet-blue-red (b) blue-violet-orange (c) violet-blue-orange (d) violet-blue-yellow
33. 33.🧮 Two equal 1000 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
34. 34.🔐 Who should decide which smart devices go in a child’s room? (a) the app’s adverts (b) nobody at all (c) an online stranger (d) a parent or guardian
35. 35.⏱️ What does “wait 500 ms” do? (a) pauses for half a second (b) waits 500 seconds (c) blinks 500 times (d) turns the LED off
36. 36.🧮 Two equal 40 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
37. 37.💡 2 identical bulbs are joined in parallel (each on its own side-by-side path) with a battery and a closed switch on the main wire. Bulb 1 is taken out of its holder. How many bulbs glow?
38. 38.🔁 repeat 2 times { repeat 3 times { beep } }
    How many beeps are there?
39. 39.True or false: on a cell, “the shorter symbol line” means the + (positive) end. (a) False (b) True
40. 40.🌐 A weather station sends one reading every 15 seconds. How many readings does it send in 1 minute?

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