Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 646 · 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.🔁 repeat 6 times { repeat 2 times { beep } }
   How many beeps are there?
2. 2.🔺 A current of 1.5 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
3. 3.True or false: on a cell, “the end with a bump” means the + (positive) end. (a) True (b) False
4. 4.🌐 Is a Wi-Fi weather station an IoT device? (a) an IoT device (b) not an IoT device
5. 5.💡 An LED (with its resistor) is on pin 8. All pins start LOW. The program runs once:
   set pin 7 HIGH
   set pin 8 HIGH
   set pin 8 LOW
   Is the LED ON or OFF at the end? (a) ON (b) OFF
6. 6.⚠️ Is it safe to touch a switch when wet? (a) safe (b) not safe
7. 7.⚡ A home appliance on the 230 V mains takes 5 A. What is its power (in watts)?
8. 8.🔺 A 10 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
9. 9.⚠️ Is it safe to build with an adult near? (a) safe (b) not safe
10. 10.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a brass key. Does the bulb glow? (a) Yes (b) No
11. 11.📏 In the water-pipe picture of a circuit, voltage is like … (a) the water tank lid (b) the tap handle (c) the water pressure (d) the pipe colour
12. 12.🔐 Is it a good or a risky habit to set a strong password? (a) risky habit (b) good habit
13. 13.⚙️ Which actuator would you use to show the temperature? (a) a pump (b) a motor (c) an LED (d) a display
14. 14.🔁 x = 3
    repeat 4 times { x = x × 2 }
    What is x at the end?
15. 15.💡 A red LED uses 2 V and should get 20 mA. It runs from a 5 V supply. What resistor (in ohms) is needed in series?
16. 16.What does a transistor do? (a) glows using little power (b) boosts a small signal (c) makes a beeping sound (d) senses how hot it is
17. 17.⏱️ How many milliseconds is a wait of 4.3 seconds?
18. 18.💡 Does it save or waste electricity to unplug idle chargers? (a) saves electricity (b) wastes electricity
19. 19.🔦 A circuit has a new cell, a bulb with a broken filament and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a ceramic cup. Does the bulb glow? (a) Yes (b) No
20. 20.Which of these mainly makes sound? (a) an electric kettle (b) an electric drill (c) a buzzer (d) an exhaust fan
21. 21.What does the Wi-Fi link do? (a) reads values, decides (b) shows data to you (c) carries the data (d) acts on a command
22. 22.🔋 What is a battery? (a) a kind of bulb (b) two or more cells joined (c) a switch with a lid (d) one single wire
23. 23.🤖 if (temperature > 38) { show “Hot” } else if (temperature > 24) { show “Warm” } else { show “Cool” }
    The temperature is 39 °C. What is shown? (a) Cool (b) Warm (c) Hot
24. 24.True or false: on an LED, the round-side leg is the anode (+). (a) True (b) False
25. 25.🧮 Resistors of 22 Ω, 10 Ω and 10 Ω are joined in series. What is the total resistance (in ohms)?
26. 26.🔋 On a cell, does “usually the black wire” mean the + end or the − end? (a) − (negative) (b) + (positive)
27. 27.🔘 A cell, a bulb and switches A and B are joined one after another in a single loop (series). A is ON and B is OFF. Does the bulb glow? (a) No (b) Yes
28. 28.💡 An LED (with its resistor) is on pin 7. All pins start LOW. The program runs once:
    set pin 7 HIGH
    set pin 8 LOW
    Is the LED ON or OFF at the end? (a) ON (b) OFF
29. 29.⚡ What does an electric toy car mainly change electricity into? (a) heat (b) movement (c) light (d) sound
30. 30.True or false: an electric iron mainly gives out heat. (a) False (b) True
31. 31.🧾 A family uses 140 units of electricity in a month and each unit costs ₹8. What is the bill (in ₹)?
32. 32.Which drawing is the symbol for a resistor? (a) a dot where wires meet (b) two or more cell symbols (c) a straight line (d) a small empty box
33. 33.Which drawing is the symbol for a capacitor? (a) a circle with a cross (b) a circle with M inside (c) a long and a short line (d) two equal parallel lines
34. 34.🧮 Resistors of 470 Ω, 100 Ω and 20 Ω are joined in series. What is the total resistance (in ohms)?
35. 35.⚡ A 2.4 W device works on 12 V. What current does it take (in amperes)? =
36. 36.🧩 Which component smooths a wobbly supply? (a) transistor (b) potentiometer (c) thermistor (d) capacitor
37. 37.⚡ A 6 W device works on 3 V. What current does it take (in amperes)? =
38. 38.🔋 4 identical 1.2 V cells are joined in series (+ of one cell to − of the next). What is the total voltage (in volts)? =
39. 39.🔁 Is the circuit closed or open if the switch is ON? (a) closed (b) open
40. 40.📏 Voltmeter or ammeter: which one measures current? (a) voltmeter (b) ammeter

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