Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 759 · 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 current of 20 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
2. 2.💡 A blue LED uses 3 V and should get 10 mA. It runs from a 6 V supply. What resistor (in ohms) is needed in series?
3. 3.🔦 A circuit has a new cell, a good bulb and a switch that is OFF. All the wires are firmly joined. A gap in one wire is bridged by a woollen thread. Does the bulb glow? (a) No (b) Yes
4. 4.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the filament (b) the glass (c) the switch (d) the base
5. 5.🔺 A current of 0.5 A flows when 5 V is joined across a resistor. What is its resistance (in ohms)?
6. 6.🔋 How many 1.5 V cells must be joined in series to give 4.5 V?
7. 7.⚡ Which formula gives electric power? (a) P = V ÷ I (b) P = V × I (c) P = I ÷ V (d) P = V + I
8. 8.True or false: on an LED, the leg by the flat edge is the cathode (−). (a) True (b) False
9. 9.🔁 count = 3
   while (count < 28) { count = count + 5 }
   How many times does the loop run?
10. 10.📏 Voltmeter or ammeter: which one is joined in series? (a) ammeter (b) voltmeter
11. 11.🤖 if (temperature > 25) { fan ON } else { fan OFF }
    The temperature sensor reads 20 °C. What happens? (a) fan ON (b) fan OFF
12. 12.Which of these is an input? (a) a motor (b) a speaker (c) a motion sensor (d) a small display
13. 13.🌐 A weather station sends one reading every 60 seconds. How many readings does it send in 2 minutes?
14. 14.🔍 For a microcontroller, is a sensor an input or an output? (a) a fuse (b) an input (c) a power source (d) an output
15. 15.🤖 Does a microwave oven usually have a microcontroller inside? (a) No (b) Yes
16. 16.True or false: to take cells out after use is not safe. (a) True (b) False
17. 17.🔗 Series or parallel circuit: “a break stops every bulb”? (a) parallel (b) series
18. 18.🌈 A resistor has the colour bands yellow, black, brown. What is its value (in ohms)?
19. 19.⏱️ repeat 7 times { buzzer ON; wait 500 ms; buzzer OFF; wait 300 ms }
    How many milliseconds does this take in all?
20. 20.📏 Voltmeter or ammeter: which one measures current? (a) voltmeter (b) ammeter
21. 21.💡 An LED is joined to a 9 V battery through a 220 Ω resistor; its long leg goes to the + side and its short leg to the − side. What happens? (a) does not light (b) may burn out (c) lights up
22. 22.🧮 Adding another resistor in series makes the total resistance … (a) bigger (b) zero (c) smaller (d) stay the same
23. 23.Which of these is a good habit? (a) share the Wi-Fi key (b) ignore update messages (c) turn off unused gadgets (d) reuse one password
24. 24.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets bigger (b) stays the same (c) becomes zero (d) gets smaller
25. 25.🤖 if (distance < 30) { buzzer beeps } else { buzzer is silent }
    The distance sensor reads 38 cm. What happens? (a) buzzer beeps (b) buzzer is silent
26. 26.🔺 In the V-I-R triangle, how do we find R? (a) R = V × I (b) R = V ÷ I (c) R = I ÷ V (d) R = V + I
27. 27.Which of these is an insulator? (a) a brass key (b) a copper wire (c) a cotton thread (d) a steel spoon
28. 28.True or false: the voltmeter is joined in series. (a) True (b) False
29. 29.🧩 Which component smooths a wobbly supply? (a) capacitor (b) buzzer (c) diode (d) motor
30. 30.Which of these is measured in volts (V)? (a) how much a part resists (b) power (c) current (d) the push of a cell
31. 31.True or false: to read app permissions is a good habit. (a) False (b) True
32. 32.Which drawing is the symbol for a wire? (a) a circle with a cross (b) a long and a short line (c) a plain rectangle (d) a straight line
33. 33.🤖 if (light < 400 AND motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 60 and motion is not detected (false). What happens? (a) porch lamp ON (b) porch lamp OFF
34. 34.🔍 Which is the odd one out? (a) climb an electric pole (b) touch a fallen wire (c) stay away from pylons (d) touch a switch when wet
35. 35.✏️ In a cell symbol, which line is the + terminal? (a) the longer line (b) both lines (c) the shorter line (d) neither line
36. 36.🌐 A weather station sends one reading every 60 seconds. How many readings does it send in 6 minutes?
37. 37.💡 Why is house wiring done in parallel? (a) to save copper only (b) so all go off together (c) to make bulbs dim (d) each gets full voltage
38. 38.True or false: “own switch for each bulb” is true of a parallel circuit. (a) True (b) False
39. 39.🗺️ In an input → process → output plan, is “decide if soil is dry” the input, the process or the output? (a) output (b) input (c) process
40. 40.🔌 Is a ceramic cup a conductor or an insulator? (a) a conductor (b) an insulator

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