Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 611 · 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 red LED (it uses 2 V) is joined with a 150 Ω resistor to a 4.25 V supply. What current flows (in mA)?
2. 2.🔘 When a switch is ON, the circuit is … (a) open (b) cut (c) closed (d) broken
3. 3.🔁 x = 3
   repeat 2 times { x = x × 2 }
   What is x at the end?
4. 4.Which of these is a conductor? (a) a wooden stick (b) a ceramic cup (c) a copper wire (d) a rubber band
5. 5.🔌 Is a ceramic cup a conductor or an insulator? (a) a conductor (b) an insulator
6. 6.🤖 if (moisture < 30) { pump ON } else { pump OFF }
   The soil moisture sensor reads 46 %. What happens? (a) pump OFF (b) pump ON
7. 7.⚡ A 0.15 W device works on 1.5 V. What current does it take (in amperes)? =
8. 8.Which of these gives us electricity? (a) a power station (b) a refrigerator (c) a television (d) a washing machine
9. 9.⚡ Power tells us … (a) energy used each second (b) the size of a cell (c) the colour of light (d) the length of a wire
10. 10.True or false: to fly a kite near wires is not safe. (a) True (b) False
11. 11.🔍 Which is the odd one out? (a) dry your hands first (b) build with an adult near (c) take cells out after use (d) touch a fallen wire
12. 12.True or false: on a cell, “the longer symbol line” means the + (positive) end. (a) False (b) True
13. 13.🔁 What does “count = count + 1” do? (a) takes 1 away (b) prints 1 (c) sets count to 1 (d) adds 1 to count
14. 14.💡 Does it save or waste electricity to leave the TV on standby? (a) wastes electricity (b) saves electricity
15. 15.🤖 if (sound > 70) { red LED ON } else { green LED ON }
    The sound sensor reads 57. What happens? (a) green LED ON (b) red LED ON
16. 16.🔌 Is a plastic straw a conductor or an insulator? (a) an insulator (b) a conductor
17. 17.🗺️ In an input → process → output plan, is “a temperature reading” the input, the process or the output? (a) output (b) input (c) process
18. 18.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
19. 19.True or false: “a button: pressed or not” is an analog signal. (a) True (b) False
20. 20.True or false: to warn of a gas leak, use a rain sensor. (a) False (b) True
21. 21.🔺 A current of 3 A flows when 18 V is joined across a resistor. What is its resistance (in ohms)?
22. 22.🔁 x = 2
    repeat 4 times { x = x × 2 }
    What is x at the end?
23. 23.Which of these is the output? (a) the pump turns on (b) decide if soil is dry (c) count button presses (d) a button press
24. 24.What does an LED do? (a) is a resistance knob (b) senses how hot it is (c) glows using little power (d) smooths a wobbly supply
25. 25.What does a potentiometer do? (a) blows if current is high (b) limits the current (c) is a resistance knob (d) has coloured bands
26. 26.⏱️ loop forever { LED ON; wait 1850 ms; LED OFF; wait 150 ms }
    How many times does the LED blink in 18 seconds?
27. 27.Which job needs a light sensor? (a) make a parking alarm (b) open blinds at sunrise (c) stop a robot near walls (d) warn of a gas leak
28. 28.✏️ In a circuit diagram, which part is drawn as a straight line? (a) switch (b) diode (c) motor (d) wire
29. 29.True or false: power is measured in volts (V). (a) True (b) False
30. 30.⚡ A 36 W device works on 24 V. What current does it take (in amperes)? =
31. 31.🔌 Most metals are good … (a) batteries (b) insulators (c) magnets only (d) conductors
32. 32.🔍 Which is the odd one out? (a) a siren (b) a loudspeaker (c) a doorbell (d) an electric kettle
33. 33.🌈 A gold fourth band on a resistor means the value may be off by … (a) 50 % (b) 0 % (c) 25 % (d) 5 %
34. 34.🧮 Adding another resistor in series makes the total resistance … (a) bigger (b) stay the same (c) smaller (d) zero
35. 35.⏱️ A program says “wait 3250 ms”. How many seconds is that? =
36. 36.Which of these is safe? (a) open a phone charger (b) dry your hands first (c) touch a switch when wet (d) climb an electric pole
37. 37.🔁 count = 10
    repeat 4 times { count = count + 2 }
    What is count at the end?
38. 38.⏱️ loop forever { LED ON; wait 100 ms; LED OFF; wait 800 ms }
    How many milliseconds does one blink (ON + OFF) take?
39. 39.Which drawing is the symbol for a diode? (a) triangle against a bar (b) a small empty box (c) a circle with a cross (d) a circle with M inside
40. 40.🔋 5 identical 1.2 V cells are joined side by side in parallel (all + ends together, all − ends together). What is the voltage across them (in volts)? =

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