Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 401 · 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.🔍 Which is the odd one out? (a) leave the TV on standby (b) use LED lamps (c) use old filament bulbs (d) run fans in empty rooms
2. 2.🤖 if (temperature > 30) { fan ON } else { fan OFF }
   The temperature sensor reads 27 °C. What happens? (a) fan ON (b) fan OFF
3. 3.🔍 Which is the odd one out? (a) a steel spoon (b) a plastic ruler (c) a wooden stick (d) a paper strip
4. 4.True or false: “one out, the rest glow” is true of a parallel circuit. (a) False (b) True
5. 5.🔋 How many 2 V cells must be joined in series to give 6 V?
6. 6.💡 What does LED stand for? (a) low energy device (b) large electric dial (c) light energy dial (d) light-emitting diode
7. 7.🤖 Does a digital thermometer usually have a microcontroller inside? (a) Yes (b) No
8. 8.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 4 hours. How many watt-hours (Wh) are saved?
9. 9.🔁 count = 2
   repeat 9 times { count = count + 8 }
   What is count at the end?
10. 10.⚡ A device works on 1.5 V and takes 0.5 A. What is its power (in watts)? =
11. 11.⚠️ Is it safe to open a phone charger? (a) safe (b) not safe
12. 12.⚡ A home appliance on the 230 V mains takes 4 A. What is its power (in watts)?
13. 13.🤖 if (temperature > 38) { show “Hot” } else if (temperature > 26) { show “Warm” } else { show “Cool” }
    The temperature is 31 °C. What is shown? (a) Warm (b) Cool (c) Hot
14. 14.🔘 Two switches are in parallel (side by side). When does the bulb glow? (a) only when both are OFF (b) never (c) when either is ON (d) only when both are ON
15. 15.🔋 How many 3 V cells must be joined in series to give 9 V?
16. 16.🌈 A gold fourth band on a resistor means the value may be off by … (a) 25 % (b) 50 % (c) 5 % (d) 0 %
17. 17.🔍 Which is the odd one out? (a) check if temp > 30 (b) a button press (c) a motion sensor signal (d) a temperature reading
18. 18.True or false: a laptop has no screen of its own. (a) True (b) False
19. 19.🔺 A 5 V supply is joined across a 200 Ω resistor. What current flows (in milliamperes, mA)?
20. 20.True or false: to open blinds at sunrise, use a distance sensor. (a) False (b) True
21. 21.Which of these is true of a series circuit? (a) one out, the rest glow (b) one bulb out, all go out (c) own switch for each bulb (d) many paths for current
22. 22.🔁 What does a variable do in a program? (a) stores a value (b) joins two wires (c) measures light (d) blinks an LED
23. 23.True or false: aluminium foil is an insulator. (a) False (b) True
24. 24.⏱️ What does “wait 500 ms” do? (a) waits 500 seconds (b) pauses for half a second (c) turns the LED off (d) blinks 500 times
25. 25.💡 Does it save or waste electricity to use old filament bulbs? (a) saves electricity (b) wastes electricity
26. 26.🔺 A current of 0.2 A flows when 3 V is joined across a resistor. What is its resistance (in ohms)?
27. 27.What does a capacitor do? (a) glows using little power (b) senses how bright it is (c) stores a little charge (d) beeps for an alarm
28. 28.True or false: “check if temp > 30” is the process. (a) False (b) True
29. 29.💡 5 identical bulbs are joined in series with a battery and a closed switch on the main wire. Bulb 3 is taken out of its holder. How many bulbs glow?
30. 30.🤖 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
31. 31.🔋 On a cell, does “usually the black wire” mean the + end or the − end? (a) + (positive) (b) − (negative)
32. 32.Which of these mainly makes sound? (a) a night lamp (b) an exhaust fan (c) an electric toy car (d) a buzzer
33. 33.🤖 “if (A AND B)” is true when … (a) both A and B are true (b) only A is true (c) only B is true (d) both are false
34. 34.⚡ Power tells us … (a) the length of a wire (b) the colour of light (c) the size of a cell (d) energy used each second
35. 35.True or false: “count button presses” is the process. (a) False (b) True
36. 36.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 460 Ω resistor? (a) yellow-blue-black (b) yellow-blue-brown (c) yellow-blue-red (d) blue-yellow-brown
37. 37.🔌 Which part of a screwdriver should an electrician hold? (a) the steel shaft (b) the plastic handle (c) the bare end (d) the metal tip
38. 38.✏️ In a circuit diagram, which part is drawn as triangle, bar and arrows? (a) wire (b) battery (c) motor (d) LED
39. 39.🔁 count = 6
    repeat 10 times { count = count + 3 }
    What is count at the end?
40. 40.🔍 A distance sensor sends a sound pulse and hears the echo 16 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?

Free electronics lessons, practice and worksheets at talentjr.in/electronics-for-kids