Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 455 · 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 4 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
2. 2.🔺 A 4 V supply is joined across a 200 Ω resistor. What current flows (in milliamperes, mA)?
3. 3.⚠️ Why must we never touch switches with wet hands? (a) water makes it cold (b) it spoils the paint (c) it is just untidy (d) water carries current
4. 4.🔁 Is the circuit closed or open if all wires are joined? (a) open (b) closed
5. 5.🔍 Which is the odd one out? (a) a motion sensor signal (b) check if temp > 30 (c) a button press (d) a temperature reading
6. 6.⚠️ Is it safe to poke things in a socket? (a) not safe (b) safe
7. 7.💡 Old festival light strings went fully dark when one bulb failed. How were they joined? (a) in series (b) in parallel (c) not joined (d) by Wi-Fi
8. 8.True or false: on a cell, “the end with a bump” means the + (positive) end. (a) True (b) False
9. 9.💡 3 identical bulbs are joined in parallel (each on its own side-by-side path) with a battery and a closed switch on the main wire. Bulb 3 is taken out of its holder. How many bulbs glow?
10. 10.⚙️ What is an actuator? (a) a sensor (b) a battery (c) an output that acts (d) a program
11. 11.💡 Does it save or waste electricity to leave fridge door open? (a) wastes electricity (b) saves electricity
12. 12.🔍 Which is the odd one out? (a) stay away from pylons (b) use a cable with cuts (c) touch a switch when wet (d) use mains for a project
13. 13.🔺 A current of 3 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
14. 14.🔁 total = 0
    for i = 1 to 10 { total = total + i }
    What is total at the end?
15. 15.True or false: “one out, the rest glow” is true of a series circuit. (a) False (b) True
16. 16.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
17. 17.What does a potentiometer do? (a) turns a fan or wheels (b) lets current go one way (c) is a resistance knob (d) boosts a small signal
18. 18.True or false: if a cell is taken out, the circuit is closed and current flows. (a) False (b) True
19. 19.🔋 Does a cell give electricity or use electricity? (a) gives electricity (b) uses electricity
20. 20.🧮 Adding another resistor in series makes the total resistance … (a) stay the same (b) bigger (c) smaller (d) zero
21. 21.⚡ A device works on 1.5 V and takes 0.1 A. What is its power (in watts)? =
22. 22.True or false: on a cell, “the flat end” means the − (negative) end. (a) False (b) True
23. 23.💡 3 identical bulbs are joined in series with a battery and a closed switch on the main wire. All the bulbs are in place. Does bulb 1 glow? (a) Yes (b) No
24. 24.Which job is done by the main chip? (a) brings power and code (b) keeps the voltage steady (c) runs the program (d) connect sensors and LEDs
25. 25.💡 In a parallel circuit, one bulb breaks. What happens to the others? (a) they explode (b) they keep glowing (c) they get dimmer (d) they all go out
26. 26.🌐 A weather station sends one reading every 10 seconds. How many readings does it send in 5 minutes?
27. 27.🗺️ In an input → process → output plan, is “a motion sensor signal” the input, the process or the output? (a) output (b) input (c) process
28. 28.🧮 A 1 V battery is joined to 2 Ω and 8 Ω resistors in series. What current flows (in amperes)? =
29. 29.🧭 Which part of a microcontroller board brings power and code? (a) the reset button (b) the USB port (c) the voltage regulator (d) the pins
30. 30.🔺 A current of 20 mA flows through a 120 Ω resistor. What is the voltage across it (in volts)? =
31. 31.🔁 What does “count = count + 1” do? (a) sets count to 1 (b) prints 1 (c) adds 1 to count (d) takes 1 away
32. 32.🧮 Four equal 20 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
33. 33.⏱️ loop forever { LED ON; wait 750 ms; LED OFF; wait 250 ms }
    How many milliseconds does one blink (ON + OFF) take?
34. 34.True or false: triangle against a bar is the symbol for a resistor. (a) False (b) True
35. 35.🤖 if (light < 400 AND motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 500 and motion is detected (true). What happens? (a) porch lamp OFF (b) porch lamp ON
36. 36.🧾 A family uses 50 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
37. 37.True or false: on a cell, “usually the red wire” means the + (positive) end. (a) False (b) True
38. 38.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
39. 39.True or false: “each gets the full volts” is true of a parallel circuit. (a) False (b) True
40. 40.Which of these means the circuit is closed? (a) a cell is taken out (b) all wires are joined (c) the bulb is unscrewed (d) a wire is cut

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