Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 795 · 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.🔐 Is it a good or a risky habit to read app permissions? (a) risky habit (b) good habit
2. 2.⏱️ How many milliseconds is a wait of 0.4 seconds?
3. 3.⚠️ Is it safe to keep drinks far away? (a) not safe (b) safe
4. 4.🧮 Adding another resistor in series makes the total resistance … (a) smaller (b) bigger (c) stay the same (d) zero
5. 5.True or false: one tall, one short bar is the symbol for a capacitor. (a) False (b) True
6. 6.🔘 Which kind of switch stays where you flip it? (a) a toggle switch (b) a reed switch (c) a slide switch (d) a push button
7. 7.💡 An LED (with its resistor) is on pin 8. All pins start LOW. The program runs once:
   set pin 7 HIGH
   set pin 7 LOW
   set pin 8 LOW
   set pin 8 LOW
   set pin 7 LOW
   Is the LED ON or OFF at the end? (a) ON (b) OFF
8. 8.🔍 Which is the odd one out? (a) an app-controlled bulb (b) a Wi-Fi doorbell camera (c) a plain wall switch (d) a fitness band with app
9. 9.🔋 How many 1.2 V cells must be joined in series to give 4.8 V?
10. 10.⏱️ loop forever { LED ON; wait 100 ms; LED OFF; wait 100 ms }
    How many times does the LED blink in 8 seconds?
11. 11.🤖 if (distance < 20) { buzzer beeps } else { buzzer is silent }
    The distance sensor reads 23 cm. What happens? (a) buzzer beeps (b) buzzer is silent
12. 12.🧩 A capacitor in a circuit can … (a) spin a wheel (b) measure heat (c) store charge briefly (d) make light
13. 13.🔺 A current of 25 mA flows when 6.25 V is joined across a resistor. What is its resistance (in ohms)?
14. 14.🧩 Which component senses how bright it is? (a) fuse (b) LDR (c) diode (d) motor
15. 15.🔐 Why install updates on IoT devices? (a) they make it heavier (b) they change the colour (c) they delete the Wi-Fi (d) they fix security holes
16. 16.Which job needs a temperature sensor? (a) warn of a gas leak (b) keep an incubator warm (c) switch on lamps at dusk (d) open blinds at sunrise
17. 17.What does a transistor do? (a) senses how bright it is (b) lets current go one way (c) stores a little charge (d) boosts a small signal
18. 18.⏱️ loop forever { LED ON; wait 100 ms; LED OFF; wait 500 ms }
    How many milliseconds does one blink (ON + OFF) take?
19. 19.Which of these is an IoT device? (a) a plain table fan (b) a fitness band with app (c) a wind-up clock (d) a plain wall switch
20. 20.📶 How many states can a digital pin have? (a) ten (b) a thousand (c) two (d) one
21. 21.🤖 “if (A AND B)” is true when … (a) only B is true (b) both A and B are true (c) both are false (d) only A is true
22. 22.True or false: a small empty box is the symbol for a wire. (a) True (b) False
23. 23.True or false: a push button closes near a magnet. (a) True (b) False
24. 24.🧩 Which component smooths a wobbly supply? (a) LED (b) potentiometer (c) capacitor (d) resistor
25. 25.✏️ In a cell symbol, which line is the + terminal? (a) both lines (b) the longer line (c) neither line (d) the shorter line
26. 26.⚠️ What protects home wiring by melting or tripping when too much current flows? (a) a long wire (b) a bulb (c) a plug top (d) a fuse or MCB
27. 27.🌈 A resistor has the colour bands white, yellow, red. What is its value in kilo-ohms (kΩ)? =
28. 28.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets bigger (b) gets smaller (c) stays the same (d) becomes zero
29. 29.True or false: “an alert on the phone” is the process. (a) True (b) False
30. 30.Which of these has no microcontroller inside? (a) a digital thermometer (b) a microwave oven (c) a wind-up toy (d) a smart watch
31. 31.Which of these is an input? (a) a water pump (b) a buzzer (c) a temperature sensor (d) a small display
32. 32.🤖 In “if (temp > 30)”, what runs when temp is exactly 30? (a) the else part (b) neither part (c) the if part (d) both parts
33. 33.Which of these is safe? (a) use mains for a project (b) open a phone charger (c) use a cable with cuts (d) build with an adult near
34. 34.🔢 To plan an electronics project, what comes right after “draw the circuit diagram”? (a) pick a problem to solve (b) build it with an adult (c) list inputs and outputs (d) test it and fix it
35. 35.🧮 Resistors of 10 Ω, 20 Ω and 68 Ω are joined in series. What is the total resistance (in ohms)?
36. 36.True or false: on an LED, the round-side leg is the cathode (−). (a) False (b) True
37. 37.🔋 How many 3 V cells must be joined in series to give 21 V?
38. 38.🌈 A resistor has the colour bands grey, yellow, yellow. What is its value in kilo-ohms (kΩ)? =
39. 39.True or false: to keep drinks far away is safe. (a) True (b) False
40. 40.🔍 Which is the odd one out? (a) a light sensor (b) a sound sensor (c) a push button (d) a motor

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