Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 171 · 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.🌈 In the resistor colour code, which number does violet stand for?
2. 2.🤖 if (temperature > 32) { show “Hot” } else if (temperature > 21) { show “Warm” } else { show “Cool” }
   The temperature is 34 °C. What is shown? (a) Warm (b) Hot (c) Cool
3. 3.🔋 On a cell, does “the longer symbol line” mean the + end or the − end? (a) + (positive) (b) − (negative)
4. 4.⏱️ repeat 3 times { buzzer ON; wait 800 ms; buzzer OFF; wait 1000 ms }
   How many milliseconds does this take in all?
5. 5.⚡ Which formula gives electric power? (a) P = V + I (b) P = V × I (c) P = V ÷ I (d) P = I ÷ V
6. 6.🔋 On a cell, does “the end with a bump” mean the + end or the − end? (a) − (negative) (b) + (positive)
7. 7.Which of these is an insulator? (a) a safety pin (b) a metal paper clip (c) a steel coin (d) a plastic ruler
8. 8.⚡ A home appliance on the 230 V mains takes 8 A. What is its power (in watts)?
9. 9.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 16 Ω resistor? (a) blue-brown-black (b) brown-blue-brown (c) red-blue-black (d) brown-blue-black
10. 10.🌈 A gold fourth band on a resistor means the value may be off by … (a) 50 % (b) 0 % (c) 25 % (d) 5 %
11. 11.🔺 A current of 1 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
12. 12.🔺 A current of 25 mA flows when 6.25 V is joined across a resistor. What is its resistance (in ohms)?
13. 13.⏱️ loop forever { LED ON; wait 450 ms; LED OFF; wait 50 ms }
    How many times does the LED blink in 3 seconds?
14. 14.🔺 A current of 20 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
15. 15.⚡ A home appliance on the 230 V mains takes 1.5 A. What is its power (in watts)?
16. 16.True or false: “the fan starts” is the output. (a) True (b) False
17. 17.🔺 A 0.8 V supply is joined across an 8 Ω resistor. What current flows (in amperes)? =
18. 18.🔁 What do we call a circuit with a break in it? (a) a series circuit (b) an open circuit (c) a full circuit (d) a closed circuit
19. 19.🤖 if (distance < 30) { buzzer beeps } else { buzzer is silent }
    The distance sensor reads 27 cm. What happens? (a) buzzer beeps (b) buzzer is silent
20. 20.💡 Does it save or waste electricity to iron one shirt at a time? (a) wastes electricity (b) saves electricity
21. 21.🧩 Which component smooths a wobbly supply? (a) LED (b) capacitor (c) buzzer (d) diode
22. 22.🔁 x = 1
    repeat 4 times { x = x × 2 }
    What is x at the end?
23. 23.🔋 How many volts does one ordinary torch cell give? (a) 15 V (b) 230 V (c) 1.5 V (d) 0.5 V
24. 24.🔐 Is it a good or a risky habit to set a strong password? (a) risky habit (b) good habit
25. 25.🔋 Cells joined + to − in a row (series) give … (a) the same voltage (b) a smaller voltage (c) no voltage (d) a bigger voltage
26. 26.🔍 Which is the odd one out? (a) a motion sensor (b) a light sensor (c) a servo motor (d) a sound sensor
27. 27.⚡ What does a traffic signal mainly change electricity into? (a) heat (b) movement (c) sound (d) light
28. 28.⚡ A home appliance on the 230 V mains takes 1 A. What is its power (in watts)?
29. 29.⚙️ What is an actuator? (a) a sensor (b) a program (c) a battery (d) an output that acts
30. 30.Which of these is an output? (a) a turning knob (b) a water pump (c) a push button (d) a temperature sensor
31. 31.⏱️ repeat 2 times { buzzer ON; wait 300 ms; buzzer OFF; wait 600 ms }
    How many milliseconds does this take in all?
32. 32.🤖 How does a new program get onto a microcontroller board? (a) sent by sound (b) drawn with a pen (c) uploaded over USB (d) typed on the chip
33. 33.True or false: a circle with A inside is the symbol for an ammeter. (a) True (b) False
34. 34.🔍 Which is the odd one out? (a) a motion sensor (b) a temperature sensor (c) a small display (d) a light sensor
35. 35.🔺 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
36. 36.🔁 count = 3
    while (count < 38) { count = count + 5 }
    How many times does the loop run?
37. 37.⚠️ Is it safe to climb an electric pole? (a) not safe (b) safe
38. 38.⚙️ Which actuator would you use to move water to plants? (a) a servo motor (b) a pump (c) an LED (d) a motor
39. 39.💡 6 identical bulbs are in parallel and each bulb has its own switch on its path. 3 of the switches are OFF and the rest are ON. How many bulbs glow?
40. 40.📏 How many kilowatts (kW) is 3950 W? =

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