Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 274 · 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 red LED (it uses 2 V) is joined with a 150 Ω resistor to a 4.25 V supply. What current flows (in mA)?
2. 2.✏️ In a circuit diagram, which part is drawn as two equal parallel lines? (a) bulb (b) voltmeter (c) switch (d) capacitor
3. 3.True or false: to open blinds at sunrise, use a temperature sensor. (a) True (b) False
4. 4.💡 A battery lights 5 identical bulbs joined in series. One more identical bulb is added in series. How do the bulbs glow now? (a) the same (b) brighter (c) dimmer
5. 5.🔺 A current of 0.2 A flows when 2 V is joined across a resistor. What is its resistance (in ohms)?
6. 6.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
7. 7.💡 What does LED stand for? (a) light energy dial (b) low energy device (c) large electric dial (d) light-emitting diode
8. 8.💡 A battery lights 2 identical bulbs joined in series. One more identical bulb is added in series. How do the bulbs glow now? (a) the same (b) dimmer (c) brighter
9. 9.Which of these mainly makes sound? (a) an electric toy car (b) a siren (c) a room heater (d) a mixer grinder
10. 10.🌈 A resistor has the colour bands blue, blue, red. What is its value in kilo-ohms (kΩ)? =
11. 11.🔌 Is a metal paper clip a conductor or an insulator? (a) an insulator (b) a conductor
12. 12.🔍 Which sensor would you use to make a parking alarm? (a) a sound sensor (b) a temperature sensor (c) a soil moisture sensor (d) a distance sensor
13. 13.True or false: the ammeter is joined in series. (a) True (b) False
14. 14.True or false: to poke things in a socket is safe. (a) True (b) False
15. 15.🔌 Is a plastic straw a conductor or an insulator? (a) a conductor (b) an insulator
16. 16.Which of these is true of a parallel circuit? (a) one bulb out, all go out (b) one out, the rest glow (c) a single current path (d) a break stops every bulb
17. 17.⚡ A home appliance on the 230 V mains takes 1 A. What is its power (in watts)?
18. 18.💡 In a parallel circuit, one bulb breaks. What happens to the others? (a) they keep glowing (b) they explode (c) they all go out (d) they get dimmer
19. 19.💡 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
    Is the LED ON or OFF at the end? (a) ON (b) OFF
20. 20.True or false: an electric toy car mainly gives out heat. (a) True (b) False
21. 21.Which job needs a light sensor? (a) start a fan when hot (b) make a parking alarm (c) open blinds at sunrise (d) water a dry plant
22. 22.🔦 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 plastic ruler. Does the bulb glow? (a) Yes (b) No
23. 23.🔋 What should you do with used-up cells? (a) throw them in a fire (b) cut them open (c) give them for recycling (d) bury them in soil
24. 24.True or false: an LDR senses how bright it is. (a) True (b) False
25. 25.🔐 Is it a good or a risky habit to install software updates? (a) good habit (b) risky habit
26. 26.🔺 A current of 3 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
27. 27.🔺 A current of 1 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
28. 28.⏱️ How many milliseconds are in 1 second? (a) 10 (b) 1000 (c) 100 (d) 60
29. 29.⏱️ What does “wait 500 ms” do? (a) turns the LED off (b) blinks 500 times (c) waits 500 seconds (d) pauses for half a second
30. 30.True or false: to set a strong password is a risky habit. (a) True (b) False
31. 31.⚠️ Is it safe to use small battery cells? (a) safe (b) not safe
32. 32.🔋 What is a battery? (a) a kind of bulb (b) one single wire (c) two or more cells joined (d) a switch with a lid
33. 33.⚠️ What protects home wiring by melting or tripping when too much current flows? (a) a plug top (b) a bulb (c) a fuse or MCB (d) a long wire
34. 34.True or false: the ammeter is joined across a part. (a) False (b) True
35. 35.🔁 total = 0
    for i = 1 to 11 { total = total + i }
    What is total at the end?
36. 36.🔌 Is a keypad an input or an output for a microcontroller? (a) output (b) input
37. 37.📏 Voltmeter or ammeter: which one is joined in series? (a) ammeter (b) voltmeter
38. 38.🔋 On a cell, does “the end with a bump” mean the + end or the − end? (a) − (negative) (b) + (positive)
39. 39.Which of these is true of a series circuit? (a) each gets the full volts (b) used in house wiring (c) many paths for current (d) one bulb out, all go out
40. 40.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) open (b) closed

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