Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 996 · 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.🔺 A current of 0.1 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
2. 2.🌈 A gold fourth band on a resistor means the value may be off by … (a) 5 % (b) 0 % (c) 50 % (d) 25 %
3. 3.🔺 In the V-I-R triangle, how do we find R? (a) R = I ÷ V (b) R = V ÷ I (c) R = V + I (d) R = V × I
4. 4.🔋 On a cell, does “the flat end” mean the + end or the − end? (a) + (positive) (b) − (negative)
5. 5.🤖 In “if (temp > 30)”, what runs when temp is exactly 30? (a) the else part (b) both parts (c) the if part (d) neither part
6. 6.🔢 To get a sensor reading onto a phone, which is the LAST step? (a) the cloud stores it (b) the sensor measures (c) the board reads it (d) the app shows it
7. 7.Which job needs a motor? (a) show a status light (b) spin a robot’s wheels (c) turn to an exact angle (d) move water to plants
8. 8.True or false: the voltmeter is joined across a part. (a) True (b) False
9. 9.🤖 if (light < 200 OR motion) { porch lamp ON } else { porch lamp OFF }
   The light reading is 150 and motion is not detected (false). What happens? (a) porch lamp OFF (b) porch lamp ON
10. 10.🔢 To run one loop of a plant-watering program, which comes first: “compare with the limit” or “switch the pump on/off”? (a) compare with the limit (b) switch the pump on/off
11. 11.🔁 What does a variable do in a program? (a) blinks an LED (b) joins two wires (c) measures light (d) stores a value
12. 12.True or false: if a cell is taken out, the circuit is open and no current flows. (a) False (b) True
13. 13.Which of these is an IoT device? (a) a paper calendar (b) a Wi-Fi smart plug (c) a plain wall switch (d) a pencil sharpener
14. 14.⚡ What does a table fan mainly change electricity into? (a) heat (b) light (c) movement (d) sound
15. 15.🧮 A 22 Ω resistor is joined in series with two equal 220 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
16. 16.🧮 Three equal 300 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
17. 17.🔢 To run one loop of a plant-watering program, what comes right after “switch the pump on/off”? (a) wait a few seconds (b) compare with the limit (c) read the soil sensor
18. 18.🔋 How many 1.5 V cells must be joined in series to give 7.5 V?
19. 19.💡 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 2 is taken out of its holder. How many bulbs glow?
20. 20.🤖 if (temperature > 37) { show “Hot” } else if (temperature > 20) { show “Warm” } else { show “Cool” }
    The temperature is 20 °C. What is shown? (a) Hot (b) Warm (c) Cool
21. 21.🤖 “if (A AND B)” is true when … (a) both are false (b) both A and B are true (c) only A is true (d) only B is true
22. 22.⏱️ How many milliseconds are in 1 second? (a) 10 (b) 100 (c) 60 (d) 1000
23. 23.📶 A pin that reads a push button is set as … (a) a battery (b) an output (c) a resistor (d) an input
24. 24.🔘 Two switches are in parallel (side by side). When does the bulb glow? (a) never (b) only when both are ON (c) when either is ON (d) only when both are OFF
25. 25.⏱️ loop forever { LED ON; wait 150 ms; LED OFF; wait 100 ms }
    How many times does the LED blink in 1 second?
26. 26.🤖 Where does the board keep its program when the power is off? (a) the resistor (b) the USB cable (c) flash memory (d) the power LED
27. 27.🔁 repeat 3 times { repeat 4 times { beep } }
    How many beeps are there?
28. 28.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by an iron nail. Does the bulb glow? (a) No (b) Yes
29. 29.⚡ A 36 W device works on 24 V. What current does it take (in amperes)? =
30. 30.⚡ A home appliance on the 230 V mains takes 0.5 A. What is its power (in watts)?
31. 31.Which of these means the circuit is open? (a) a wire has come loose (b) the switch is ON (c) all wires are joined (d) the loop is complete
32. 32.True or false: on a cell, “the longer symbol line” means the − (negative) end. (a) False (b) True
33. 33.🌈 In the resistor colour code, which number does black stand for?
34. 34.🔢 To run one loop of a plant-watering program, which is the FIRST step? (a) compare with the limit (b) wait a few seconds (c) read the soil sensor (d) switch the pump on/off
35. 35.🌐 A weather station sends one reading every 30 seconds. How many readings does it send in 5 minutes?
36. 36.⏱️ loop forever { LED ON; wait 650 ms; LED OFF; wait 250 ms }
    How many milliseconds does one blink (ON + OFF) take?
37. 37.🔺 A current of 2 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
38. 38.🌐 Each reading a sensor sends is 25 bytes. How many bytes do 70 readings take?
39. 39.🧮 A 220 Ω resistor is joined in series with two equal 220 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
40. 40.Which of these uses electricity? (a) a power station (b) a water pump (c) a solar panel (d) a generator

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