Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 322 · 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.🗺️ In an input → process → output plan, is “a buzzer beeps” the input, the process or the output? (a) process (b) output (c) input
2. 2.🔍 Which sensor would you use to start a fan when hot? (a) a distance sensor (b) a sound sensor (c) a temperature sensor (d) a soil moisture sensor
3. 3.🧮 A 1.4 V battery is joined to 2 Ω and 12 Ω resistors in series. What current flows (in amperes)? =
4. 4.🔍 Which is the odd one out? (a) a light sensor (b) a turning knob (c) a sound sensor (d) a servo motor
5. 5.🧭 Which part of a microcontroller board shows the board is on? (a) the main chip (b) the USB port (c) the pins (d) the power LED
6. 6.💡 An LED (with its resistor) is on pin 8. All pins start LOW. The program runs once:
   set pin 8 LOW
   set pin 7 LOW
   set pin 8 LOW
   set pin 7 LOW
   Is the LED ON or OFF at the end? (a) ON (b) OFF
7. 7.🔐 Privacy for a smart device means controlling … (a) its colour (b) its battery size (c) how loud it beeps (d) who can see your data
8. 8.💡 A red LED uses 2 V and should get 10 mA. It runs from a 12 V supply. What resistor (in ohms) is needed in series?
9. 9.Which of these is an input? (a) a small display (b) a buzzer (c) a water pump (d) a sound sensor
10. 10.🌈 In the resistor colour code, which number does green stand for?
11. 11.True or false: to measure classroom noise, use a rain sensor. (a) False (b) True
12. 12.🔘 Two switches are in series. When does the bulb glow? (a) when both are ON (b) when both are OFF (c) never (d) when either is ON
13. 13.What does a toggle switch do? (a) closes near a magnet (b) flips up or down (c) slides side to side (d) springs back when let go
14. 14.🔺 In the V-I-R triangle, how do we find I? (a) I = V × R (b) I = R ÷ V (c) I = V ÷ R (d) I = V + R
15. 15.🔐 A smart speaker is always listening for its wake word. What is a sensible habit? (a) mute it when not in use (b) tell it your passwords (c) put it in the bathroom (d) let strangers use it
16. 16.💡 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 2 glow? (a) Yes (b) No
17. 17.💡 Does it save or waste electricity to leave fridge door open? (a) saves electricity (b) wastes electricity
18. 18.True or false: a torch mainly gives out light. (a) False (b) True
19. 19.True or false: a fuse blows if current is high. (a) True (b) False
20. 20.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. Does the bulb glow? (a) No (b) Yes
21. 21.Which of these uses electricity? (a) a mobile phone (b) a solar panel (c) a cell (d) a battery
22. 22.What does the Wi-Fi link do? (a) shows data to you (b) acts on a command (c) measures the real world (d) carries the data
23. 23.🤖 if (temperature > 31) { show “Hot” } else if (temperature > 19) { show “Warm” } else { show “Cool” }
    The temperature is 13 °C. What is shown? (a) Warm (b) Cool (c) Hot
24. 24.🔺 A current of 20 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
25. 25.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
26. 26.💡 A red LED (it uses 2 V) is joined with a 150 Ω resistor to a 5 V supply. What current flows (in mA)?
27. 27.🔦 A circuit has a used-up (dead) cell, a good bulb and a switch that is ON. All the wires are firmly joined. Does the bulb glow? (a) Yes (b) No
28. 28.True or false: a resistor has coloured bands. (a) False (b) True
29. 29.🔘 A cell and a bulb are joined to 2 side-by-side paths with one switch on each path — A and B (parallel). A is ON and B is ON. Does the bulb glow? (a) No (b) Yes
30. 30.True or false: a capacitor blows if current is high. (a) False (b) True
31. 31.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a graphite rod across the gap. Does the bulb glow? (a) No (b) Yes
32. 32.🔺 A current of 25 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
33. 33.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) becomes zero (b) gets smaller (c) gets bigger (d) stays the same
34. 34.Which of these uses electricity? (a) a bicycle dynamo (b) a generator (c) a power station (d) a water pump
35. 35.What does a thermistor do? (a) turns a fan or wheels (b) blows if current is high (c) senses how hot it is (d) lets current go one way
36. 36.Which of these is a risky habit? (a) change default passwords (b) set a strong password (c) share only needed data (d) ignore update messages
37. 37.💡 An LED (with its resistor) is on pin 8. All pins start LOW. The program runs once:
    set pin 8 LOW
    set pin 8 LOW
    set pin 8 HIGH
    set pin 8 LOW
    set pin 8 HIGH
    Is the LED ON or OFF at the end? (a) ON (b) OFF
38. 38.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
39. 39.💡 6 identical bulbs are in parallel and each one takes 0.1 A. What total current (in amperes) comes from the battery? =
40. 40.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a wooden stick across the gap. Does the bulb glow? (a) No (b) Yes

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