Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 671 · 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 kind of switch works only while pressed? (a) a reed switch (b) a slide switch (c) a toggle switch (d) a push button
2. 2.🔺 A current of 20 mA flows when 2 V is joined across a resistor. What is its resistance (in ohms)?
3. 3.🔍 Which is the odd one out? (a) a sound sensor (b) a motor (c) a turning knob (d) a push button
4. 4.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) stays the same (b) gets bigger (c) gets smaller (d) becomes zero
5. 5.🔍 For a microcontroller, is a sensor an input or an output? (a) an input (b) a fuse (c) a power source (d) an output
6. 6.🔢 To run one loop of a plant-watering program, what comes right after “read the soil sensor”? (a) compare with the limit (b) wait a few seconds (c) switch the pump on/off
7. 7.💡 2 identical bulbs are joined in series with an 8 V battery (ideal wires). How many volts does each bulb get? =
8. 8.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a plastic straw across the gap. Does the bulb glow? (a) Yes (b) No
9. 9.🧩 Which component senses how bright it is? (a) LDR (b) fuse (c) resistor (d) diode
10. 10.🔋 On a cell, does “usually the red wire” mean the + end or the − end? (a) − (negative) (b) + (positive)
11. 11.Which of these is the output? (a) a motion sensor signal (b) a temperature reading (c) a soil moisture reading (d) a buzzer beeps
12. 12.🧩 Which component glows using little power? (a) capacitor (b) LED (c) buzzer (d) LDR
13. 13.🧮 Adding another resistor in series makes the total resistance … (a) zero (b) smaller (c) stay the same (d) bigger
14. 14.🤖 if (light < 200 AND motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 490 and motion is detected (true). What happens? (a) porch lamp ON (b) porch lamp OFF
15. 15.True or false: a toaster mainly makes sound. (a) True (b) False
16. 16.🧮 A 12 V battery is joined to 12 Ω and 12 Ω resistors in series. What current flows (in amperes)? =
17. 17.🔋 On a cell, does “the longer symbol line” mean the + end or the − end? (a) + (positive) (b) − (negative)
18. 18.🔺 A current of 2 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
19. 19.⚡ A home appliance on the 230 V mains takes 1.5 A. What is its power (in watts)?
20. 20.🔁 count = 4
    repeat 5 times { count = count + 9 }
    What is count at the end?
21. 21.⏱️ loop forever { LED ON; wait 1350 ms; LED OFF; wait 650 ms }
    How many times does the LED blink in 2 seconds?
22. 22.True or false: if a wire is cut, the circuit is open and no current flows. (a) True (b) False
23. 23.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
24. 24.🔺 A current of 0.1 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
25. 25.🗺️ In “input → process → output”, which part is the decision the program makes? (a) the input (b) the battery (c) the output (d) the process
26. 26.📏 Voltmeter or ammeter: which one is joined in series? (a) voltmeter (b) ammeter
27. 27.🔁 What must there be for a current to flow? (a) a complete loop (b) a broken path (c) one loose end (d) a plastic gap
28. 28.⚠️ Is it safe to throw cells in a fire? (a) safe (b) not safe
29. 29.True or false: a ceramic cup is a conductor. (a) False (b) True
30. 30.⚡ A 1.2 W device works on 6 V. What current does it take (in amperes)? =
31. 31.⚠️ Why must we never touch switches with wet hands? (a) it is just untidy (b) water carries current (c) water makes it cold (d) it spoils the paint
32. 32.Which of these mainly gives out light? (a) a water heater (b) a school bell (c) a torch (d) a toaster
33. 33.True or false: two or more cell symbols is the symbol for a battery. (a) False (b) True
34. 34.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
35. 35.🔺 A current of 1.5 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
36. 36.✏️ Why do engineers draw circuits with symbols? (a) quick and clear for all (b) to hide the circuit (c) to make it colourful (d) symbols are heavier
37. 37.🌈 A resistor has the colour bands white, yellow, yellow. What is its value in kilo-ohms (kΩ)? =
38. 38.🔁 count = 9
    repeat 3 times { count = count + 7 }
    What is count at the end?
39. 39.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a woollen thread across the gap. Does the bulb glow? (a) No (b) Yes
40. 40.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 2400 Ω resistor? (a) red-yellow-red (b) red-yellow-brown (c) yellow-red-red (d) red-yellow-orange

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