Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 193 · 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 6 V battery and one 1.5 V cell are joined in series, all facing the same way. What is the total voltage (in volts)? =
2. 2.💡 An LED (with its resistor) is on pin 7. All pins start LOW. The program runs once:
   set pin 7 HIGH
   set pin 7 HIGH
   set pin 7 HIGH
   set pin 7 HIGH
   set pin 8 LOW
   Is the LED ON or OFF at the end? (a) OFF (b) ON
3. 3.⚡ A device works on 24 V and takes 3 A. What is its power (in watts)? =
4. 4.🌈 A gold fourth band on a resistor means the value may be off by … (a) 25 % (b) 5 % (c) 50 % (d) 0 %
5. 5.🧾 One “unit” on an electricity bill is … (a) 1 ampere (b) 1 volt (c) 1 kilowatt-hour (kWh) (d) 1 watt
6. 6.⏱️ How many milliseconds is a wait of 0.2 seconds?
7. 7.⚙️ Which actuator would you use to show the temperature? (a) a servo motor (b) an LED (c) a pump (d) a display
8. 8.Which of these is not safe? (a) stop if a part gets hot (b) stay away from pylons (c) use mains for a project (d) take cells out after use
9. 9.Which of these is not safe? (a) fly a kite near wires (b) build with an adult near (c) fly kites in open fields (d) dry your hands first
10. 10.🔍 Which is the odd one out? (a) a rubber eraser (b) a copper wire (c) a steel spoon (d) a brass key
11. 11.💡 5 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 5 is taken out of its holder. Does bulb 3 glow? (a) No (b) Yes
12. 12.Which of these is true of a parallel circuit? (a) one bulb out, all go out (b) a break stops every bulb (c) one out, the rest glow (d) a single current path
13. 13.💡 Does it save or waste electricity to leave fridge door open? (a) saves electricity (b) wastes electricity
14. 14.🔘 A cell and a bulb are joined to 4 side-by-side paths with one switch on each path — A, B, C and D (parallel). A is OFF, B is ON, C is ON and D is OFF. Does the bulb glow? (a) No (b) Yes
15. 15.🔌 Most metals are good … (a) conductors (b) insulators (c) batteries (d) magnets only
16. 16.True or false: on an LED, the longer leg is the cathode (−). (a) True (b) False
17. 17.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 16000 Ω resistor? (a) brown-blue-orange (b) brown-blue-yellow (c) brown-blue-red (d) blue-brown-orange
18. 18.🔐 Is it a good or a risky habit to keep factory passwords? (a) good habit (b) risky habit
19. 19.Which of these gives us electricity? (a) a refrigerator (b) a washing machine (c) a bicycle dynamo (d) a water pump
20. 20.🔺 A current of 10 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
21. 21.⚡ A home appliance on the 230 V mains takes 5 A. What is its power (in watts)?
22. 22.⏱️ loop forever { LED ON; wait 100 ms; LED OFF; wait 300 ms }
    How many times does the LED blink in 20 seconds?
23. 23.🌐 In an IoT system, which part reads values, decides? (a) phone app (b) actuator (c) sensor (d) microcontroller
24. 24.🤖 if (light < 200 AND motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 100 and motion is detected (true). What happens? (a) porch lamp OFF (b) porch lamp ON
25. 25.True or false: “many values in a range” is an analog signal. (a) False (b) True
26. 26.💡 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?
27. 27.💡 What does LED stand for? (a) low energy device (b) large electric dial (c) light-emitting diode (d) light energy dial
28. 28.💡 A battery lights 5 identical bulbs joined in series. One more identical bulb is added in series. How do the bulbs glow now? (a) brighter (b) dimmer (c) the same
29. 29.📏 How many milliamperes (mA) is 2.4 A?
30. 30.Which of these is the process? (a) a soil moisture reading (b) an alert on the phone (c) the fan starts (d) check if temp > 30
31. 31.🏠 Which is a smart-home example? (a) a candle in a jar (b) a hand fan (c) lights on from an app (d) a printed map
32. 32.⚡ A home appliance on the 230 V mains takes 1.5 A. What is its power (in watts)?
33. 33.🧩 A capacitor in a circuit can … (a) store charge briefly (b) measure heat (c) spin a wheel (d) make light
34. 34.True or false: “many paths for current” is true of a parallel circuit. (a) True (b) False
35. 35.💡 3 identical bulbs are in parallel and each bulb has its own switch on its path. 1 of the switches is OFF and the rest are ON. How many bulbs glow?
36. 36.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) becomes zero (b) stays the same (c) gets smaller (d) gets bigger
37. 37.⚡ What does a traffic signal mainly change electricity into? (a) heat (b) movement (c) light (d) sound
38. 38.🧮 Resistors of 10 Ω, 10 Ω and 20 Ω are joined in series. What is the total resistance (in ohms)?
39. 39.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 900 Ω resistor? (a) brown-white-brown (b) white-black-black (c) white-black-red (d) white-black-brown
40. 40.Which of these gives us electricity? (a) a television (b) a washing machine (c) a refrigerator (d) a solar panel

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