Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 931 · 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 resistor has the colour bands brown, yellow, orange. What is its value (in ohms)?
2. 2.What does a resistor do? (a) limits the current (b) makes things spin (c) senses how hot it is (d) blows if current is high
3. 3.📏 Which unit measures energy used each second? (a) watt (W) (b) ampere (A) (c) volt (V) (d) ohm (Ω)
4. 4.True or false: a tilt switch stays where you flip it. (a) True (b) False
5. 5.True or false: to use mains for a project is not safe. (a) True (b) False
6. 6.💡 An LED is joined to a 9 V battery through a 220 Ω resistor; its long leg goes to the + side and its short leg to the − side. What happens? (a) does not light (b) may burn out (c) lights up
7. 7.⏱️ repeat 5 times { buzzer ON; wait 800 ms; buzzer OFF; wait 800 ms }
   How many milliseconds does this take in all?
8. 8.🧮 Resistors of 47 Ω, 220 Ω, 330 Ω and 22 Ω are joined in series. What is the total resistance (in ohms)?
9. 9.True or false: a long and a short line is the symbol for an LED. (a) False (b) True
10. 10.💡 Does it save or waste electricity to set the AC to 24 °C? (a) saves electricity (b) wastes electricity
11. 11.⚡ What does a school bell mainly change electricity into? (a) heat (b) sound (c) light (d) movement
12. 12.💡 What does LED stand for? (a) light-emitting diode (b) large electric dial (c) low energy device (d) light energy dial
13. 13.💡 An LED (with its resistor) is on pin 8. All pins start LOW. The program runs once:
    set pin 7 LOW
    set pin 7 LOW
    Is the LED ON or OFF at the end? (a) ON (b) OFF
14. 14.📶 On a 5 V board, a pin set HIGH gives about … (a) 5 V (b) 50 V (c) 0 V (d) 230 V
15. 15.What does the microcontroller do? (a) measures the real world (b) reads values, decides (c) acts on a command (d) stores data online
16. 16.🔍 Which is the odd one out? (a) a dry cork (b) a rubber eraser (c) a safety pin (d) a ceramic cup
17. 17.What does a reed switch do? (a) slides side to side (b) closes near a magnet (c) closes when tipped over (d) springs back when let go
18. 18.🔺 A current of 50 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
19. 19.📏 How many milliamperes (mA) is 2.58 A?
20. 20.🧮 A 50 Ω resistor is joined in series with two equal 20 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
21. 21.True or false: a mixer grinder mainly makes sound. (a) False (b) True
22. 22.🧮 Two resistors in parallel give a total that is … (a) more than either one (b) less than either one (c) their sum (d) always zero
23. 23.Which of these means the circuit is open? (a) the switch is ON (b) a wire has come loose (c) all wires are joined (d) the loop is complete
24. 24.🔋 5 identical 2 V cells are joined in series (+ of one cell to − of the next). What is the total voltage (in volts)? =
25. 25.Which of these is a conductor? (a) a graphite rod (b) a ceramic cup (c) a paper strip (d) a plastic ruler
26. 26.Which of these is a good habit? (a) share camera links (b) share only needed data (c) share the Wi-Fi key (d) ignore update messages
27. 27.🔗 Series or parallel circuit: “one out, the rest glow”? (a) series (b) parallel
28. 28.⚡ A 0.6 W device works on 3 V. What current does it take (in amperes)? =
29. 29.🌐 A soil sensor sends a reading to an app every 10 minutes. How many readings arrive in 3 hours?
30. 30.🤖 In “if (temp > 30)”, what runs when temp is exactly 30? (a) the if part (b) both parts (c) neither part (d) the else part
31. 31.What does a tilt switch do? (a) stays where you flip it (b) works only while pressed (c) slides side to side (d) closes when tipped over
32. 32.🔍 Which is the odd one out? (a) stay away from pylons (b) fly kites in open fields (c) take cells out after use (d) throw cells in a fire
33. 33.🔢 To run one loop of a plant-watering program, which comes first: “switch the pump on/off” or “read the soil sensor”? (a) read the soil sensor (b) switch the pump on/off
34. 34.🔺 A current of 25 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
35. 35.🔋 On a cell, does “usually the red wire” mean the + end or the − end? (a) − (negative) (b) + (positive)
36. 36.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V + I (c) P = V ÷ I (d) P = V × I
37. 37.🧾 A family uses 120 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
38. 38.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
39. 39.True or false: to keep an incubator warm, use a temperature sensor. (a) False (b) True
40. 40.⚠️ Is it safe to touch a switch when wet? (a) safe (b) not safe

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