Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 639 · 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 50 ms; LED OFF; wait 700 ms }
   How many milliseconds does one blink (ON + OFF) take?
2. 2.⚡ Power tells us … (a) the colour of light (b) the length of a wire (c) the size of a cell (d) energy used each second
3. 3.🔋 On a cell, does “the longer symbol line” mean the + end or the − end? (a) + (positive) (b) − (negative)
4. 4.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark an 88 Ω resistor? (a) white-grey-black (b) grey-grey-black (c) grey-white-black (d) grey-grey-brown
5. 5.🤖 if (light < 400 OR motion) { porch lamp ON } else { porch lamp OFF }
   The light reading is 50 and motion is detected (true). What happens? (a) porch lamp OFF (b) porch lamp ON
6. 6.True or false: to switch off empty rooms wastes electricity. (a) False (b) True
7. 7.Which of these is an input? (a) a servo motor (b) an LED (c) a light sensor (d) a small display
8. 8.Which of these is the process? (a) an alert on the phone (b) check if temp > 30 (c) a soil moisture reading (d) a buzzer beeps
9. 9.True or false: to open blinds at sunrise, use a rain sensor. (a) True (b) False
10. 10.🧮 Two equal 200 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
11. 11.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
12. 12.🔁 What do we call a circuit with a break in it? (a) an open circuit (b) a series circuit (c) a closed circuit (d) a full circuit
13. 13.🤖 Where does the board keep its program when the power is off? (a) the resistor (b) the USB cable (c) the power LED (d) flash memory
14. 14.🔺 A current of 3 A flows when 6 V is joined across a resistor. What is its resistance (in ohms)?
15. 15.🔺 In the V-I-R triangle, how do we find I? (a) I = R ÷ V (b) I = V × R (c) I = V ÷ R (d) I = V + R
16. 16.🔋 Does a water pump give electricity or use electricity? (a) gives electricity (b) uses electricity
17. 17.🔍 Which is the odd one out? (a) use old filament bulbs (b) iron one shirt at a time (c) run fans in empty rooms (d) switch off empty rooms
18. 18.🤖 Microcontroller or laptop: which one needs much more power? (a) microcontroller (b) laptop
19. 19.🔺 A 6 V supply is joined across a 300 Ω resistor. What current flows (in milliamperes, mA)?
20. 20.True or false: “a single current path” is true of a parallel circuit. (a) False (b) True
21. 21.🔍 Which is the odd one out? (a) decide if soil is dry (b) compare with a limit (c) a motion sensor signal (d) check if temp > 30
22. 22.Which of these is safe? (a) poke things in a socket (b) touch a switch when wet (c) use a cable with cuts (d) dry your hands first
23. 23.True or false: “a door: open or shut” is a digital signal. (a) False (b) True
24. 24.True or false: “bulbs share the voltage” is true of a series circuit. (a) False (b) True
25. 25.🔍 Which is the odd one out? (a) a servo motor (b) a speaker (c) a water pump (d) a sound sensor
26. 26.🧮 A 47 Ω resistor is joined in series with two equal 50 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
27. 27.Which of these is not safe? (a) dry your hands first (b) touch a fallen wire (c) stay away from pylons (d) fly kites in open fields
28. 28.💡 2 identical bulbs are joined in parallel across a 1.5 V battery (ideal wires). How many volts does each bulb get? =
29. 29.🔘 A cell, a bulb and switches A, B and C are joined one after another in a single loop (series). A is ON, B is ON and C is ON. Does the bulb glow? (a) No (b) Yes
30. 30.💡 5 identical bulbs are joined in series with a battery and a closed switch on the main wire. Bulb 5 is taken out of its holder. Does bulb 4 glow? (a) No (b) Yes
31. 31.Which of these is a conductor? (a) a steel spoon (b) a woollen thread (c) a rubber band (d) a cotton thread
32. 32.🤖 “if (A AND B)” is true when … (a) both are false (b) only B is true (c) both A and B are true (d) only A is true
33. 33.🔺 A 5 V supply is joined across a 200 Ω resistor. What current flows (in milliamperes, mA)?
34. 34.🌈 A resistor has the colour bands white, white, yellow. What is its value in kilo-ohms (kΩ)? =
35. 35.🔍 Which is the odd one out? (a) an app-controlled bulb (b) a Wi-Fi smart plug (c) a Wi-Fi doorbell camera (d) a plain wall switch
36. 36.🤖 if (light < 200 OR motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 270 and motion is not detected (false). What happens? (a) porch lamp OFF (b) porch lamp ON
37. 37.True or false: a torch mainly makes sound. (a) False (b) True
38. 38.🔌 Is an LED an input or an output for a microcontroller? (a) input (b) output
39. 39.⏱️ A program says “wait 4250 ms”. How many seconds is that? =
40. 40.🤖 if (temperature > 37) { show “Hot” } else if (temperature > 20) { show “Warm” } else { show “Cool” }
    The temperature is 27 °C. What is shown? (a) Cool (b) Hot (c) Warm

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