Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 298 · 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.💡 Does it save or waste electricity to close the fridge quickly? (a) saves electricity (b) wastes electricity
2. 2.⚡ A home appliance on the 230 V mains takes 8 A. What is its power (in watts)?
3. 3.Which job needs a motion sensor? (a) warn of a gas leak (b) switch on lamps at dusk (c) spot someone walking in (d) start a fan when hot
4. 4.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
5. 5.🧮 A 47 Ω resistor is joined in series with two equal 40 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
6. 6.True or false: the ammeter measures current. (a) False (b) True
7. 7.Which of these is not an IoT device? (a) a Wi-Fi doorbell camera (b) a Wi-Fi smart plug (c) a plain table fan (d) a smart energy meter
8. 8.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) stays the same (b) becomes zero (c) gets bigger (d) gets smaller
9. 9.True or false: to read app permissions is a risky habit. (a) True (b) False
10. 10.True or false: a dry cork is an insulator. (a) False (b) True
11. 11.True or false: “a button: pressed or not” is an analog signal. (a) True (b) False
12. 12.🔗 Series or parallel circuit: “many paths for current”? (a) series (b) parallel
13. 13.🔘 A cell, a bulb and switches A and B are joined one after another in a single loop (series). A is OFF and B is ON. Does the bulb glow? (a) No (b) Yes
14. 14.🔍 Which is the odd one out? (a) touch a fallen wire (b) dry your hands first (c) use mains for a project (d) touch a switch when wet
15. 15.Which of these is true of a parallel circuit? (a) one bulb out, all go out (b) a break stops every bulb (c) bulbs share the voltage (d) each gets the full volts
16. 16.🌐 Is a pencil sharpener an IoT device? (a) an IoT device (b) not an IoT device
17. 17.Which of these is true of a series circuit? (a) one out, the rest glow (b) a single current path (c) own switch for each bulb (d) used in house wiring
18. 18.🔺 In the V-I-R triangle, how do we find V? (a) V = I × R (b) V = I + R (c) V = I ÷ R (d) V = R ÷ I
19. 19.Which of these is a conductor? (a) a plastic straw (b) a woollen thread (c) a ceramic cup (d) a copper wire
20. 20.True or false: a buzzer is a resistance knob. (a) False (b) True
21. 21.💡 An LED (with its resistor) is on pin 7. All pins start LOW. The program runs once:
    set pin 7 LOW
    set pin 8 LOW
    set pin 7 LOW
    set pin 8 HIGH
    set pin 7 HIGH
    Is the LED ON or OFF at the end? (a) ON (b) OFF
22. 22.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
23. 23.⚡ Which formula gives electric power? (a) P = V × I (b) P = V ÷ I (c) P = I ÷ V (d) P = V + I
24. 24.Which of these means the circuit is closed? (a) the switch is ON (b) a wire is cut (c) the switch is OFF (d) a cell is taken out
25. 25.Which of these wastes electricity? (a) leave the TV on standby (b) use daylight to read (c) set the AC to 24 °C (d) close the fridge quickly
26. 26.⏱️ How many milliseconds are in 1 second? (a) 100 (b) 10 (c) 60 (d) 1000
27. 27.🔋 2 identical 1.5 V cells are joined side by side in parallel (all + ends together, all − ends together). What is the voltage across them (in volts)? =
28. 28.🔺 A current of 1.5 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
29. 29.🔁 count = 2
    while (count < 12) { count = count + 5 }
    How many times does the loop run?
30. 30.✏️ In a cell symbol, which line is the + terminal? (a) neither line (b) both lines (c) the shorter line (d) the longer line
31. 31.🔢 To get a sensor reading onto a phone, which comes first: “the cloud stores it” or “it is sent by Wi-Fi”? (a) it is sent by Wi-Fi (b) the cloud stores it
32. 32.🔌 Most metals are good … (a) magnets only (b) insulators (c) conductors (d) batteries
33. 33.🌈 A resistor has the colour bands grey, yellow, black. What is its value (in ohms)?
34. 34.🧾 A 75 W filament bulb is swapped for a 12 W LED lamp that gives about the same light. Both would run for 1 hour. How many watt-hours (Wh) are saved?
35. 35.🤖 if (light < 200 AND motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 150 and motion is detected (true). What happens? (a) porch lamp ON (b) porch lamp OFF
36. 36.🔋 4 identical 3 V cells are joined side by side in parallel (all + ends together, all − ends together). What is the voltage across them (in volts)? =
37. 37.🔁 repeat 6 times { repeat 6 times { beep } }
    How many beeps are there?
38. 38.⏱️ How many milliseconds is a wait of 3.1 seconds?
39. 39.🔍 Which is the odd one out? (a) tap unknown app links (b) reuse one password (c) keep factory passwords (d) install software updates
40. 40.⚠️ Why must we never touch switches with wet hands? (a) it is just untidy (b) water makes it cold (c) it spoils the paint (d) water carries current

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