Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 321 · 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.🧮 Resistors of 20 Ω, 10 Ω, 22 Ω and 50 Ω are joined in series. What is the total resistance (in ohms)?
2. 2.True or false: to warn of a gas leak, use a gas sensor. (a) False (b) True
3. 3.🔺 A current of 0.25 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
4. 4.🧮 Resistors of 10 Ω, 100 Ω, 10 Ω and 20 Ω are joined in series. What is the total resistance (in ohms)?
5. 5.True or false: to warn of a gas leak, use a motion sensor. (a) True (b) False
6. 6.🌐 How does a home IoT device usually send its data to the app? (a) by post (b) through a candle (c) by shouting (d) over Wi-Fi
7. 7.🤖 Microcontroller or laptop: which one has a built-in keyboard? (a) laptop (b) microcontroller
8. 8.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
9. 9.🔋 5 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)? =
10. 10.🧮 A 68 Ω resistor is joined in series with two equal 100 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
11. 11.📏 How many milliamperes (mA) is 1.46 A?
12. 12.🗺️ In an input → process → output plan, is “a motion sensor signal” the input, the process or the output? (a) process (b) input (c) output
13. 13.🔺 A current of 1.5 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
14. 14.🔺 A current of 1 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
15. 15.💡 An LED (with its resistor) is on pin 8. All pins start LOW. The program runs once:
    set pin 8 LOW
    set pin 8 HIGH
    set pin 7 HIGH
    set pin 7 LOW
    set pin 8 LOW
    Is the LED ON or OFF at the end? (a) ON (b) OFF
16. 16.🗺️ In an input → process → output plan, is “an LED lights up” the input, the process or the output? (a) input (b) output (c) process
17. 17.💡 A blue LED uses 3 V and should get 10 mA. It runs from a 5 V supply. What resistor (in ohms) is needed in series?
18. 18.🤖 if (light < 300 OR motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 450 and motion is not detected (false). What happens? (a) porch lamp ON (b) porch lamp OFF
19. 19.⚡ Power tells us … (a) the length of a wire (b) energy used each second (c) the colour of light (d) the size of a cell
20. 20.🧩 Which component boosts a small signal? (a) LED (b) transistor (c) potentiometer (d) capacitor
21. 21.💡 5 identical bulbs are in parallel and each bulb has its own switch on its path. 1 of the switches is OFF and the rest are ON. How many bulbs glow?
22. 22.🧮 Two resistors in parallel give a total that is … (a) more than either one (b) their sum (c) less than either one (d) always zero
23. 23.🔋 What is a battery? (a) a switch with a lid (b) two or more cells joined (c) a kind of bulb (d) one single wire
24. 24.Which of these is an insulator? (a) an iron nail (b) aluminium foil (c) a safety pin (d) a rubber eraser
25. 25.🔍 Which is the odd one out? (a) use daylight to read (b) leave the TV on standby (c) unplug idle chargers (d) switch off empty rooms
26. 26.True or false: a buzzer makes a beeping sound. (a) False (b) True
27. 27.🧮 Three equal 30 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
28. 28.🤖 In “if (temp > 30)”, what runs when temp is exactly 30? (a) neither part (b) both parts (c) the else part (d) the if part
29. 29.🔺 A current of 10 mA flows through a 250 Ω resistor. What is the voltage across it (in volts)? =
30. 30.Which of these is a risky habit? (a) share the Wi-Fi key (b) log out of shared phones (c) set up with a parent (d) cover unused cameras
31. 31.🤖 if (light < 300) { lamp ON } else { lamp OFF }
    The light sensor reads 402. What happens? (a) lamp OFF (b) lamp ON
32. 32.🔋 A 6 V battery and four 1.5 V cells are joined in series, all facing the same way. What is the total voltage (in volts)? =
33. 33.Which of these is true of a series circuit? (a) one out, the rest glow (b) own switch for each bulb (c) bulbs share the voltage (d) each gets the full volts
34. 34.🔺 A current of 0.5 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
35. 35.⚡ What does a ceiling fan mainly change electricity into? (a) movement (b) heat (c) light (d) sound
36. 36.🗺️ In an input → process → output plan, is “a light level reading” the input, the process or the output? (a) process (b) input (c) output
37. 37.🔋 3 identical 2 V cells are joined in series (+ of one cell to − of the next). What is the total voltage (in volts)? =
38. 38.⏱️ How many milliseconds is a wait of 4.9 seconds?
39. 39.🧮 Resistors of 150 Ω and 330 Ω are joined in series. What is the total resistance (in ohms)?
40. 40.🌐 A weather station sends one reading every 20 seconds. How many readings does it send in 1 minute?

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