Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 328 · 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 37.5 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
2. 2.🧮 Two equal 20 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
3. 3.💡 4 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?
4. 4.🧮 Two resistors in parallel give a total that is … (a) less than either one (b) more than either one (c) always zero (d) their sum
5. 5.📏 How many ohms make 1 kilo-ohm (kΩ)? (a) 10 (b) 100 (c) 1024 (d) 1000
6. 6.🔺 A 0.75 V supply is joined across a 3 Ω resistor. What current flows (in amperes)? =
7. 7.⚡ A bicycle dynamo changes which kind of energy into electricity? (a) chemical energy (b) sound energy (c) movement energy (d) light energy
8. 8.🔁 x = 1
   repeat 4 times { x = x × 2 }
   What is x at the end?
9. 9.🔢 To get a sensor reading onto a phone, what comes right after “it is sent by Wi-Fi”? (a) the cloud stores it (b) the sensor measures (c) the board reads it (d) the app shows it
10. 10.🤖 if (light < 200) { lamp ON } else { lamp OFF }
    The light sensor reads 55. What happens? (a) lamp ON (b) lamp OFF
11. 11.🧩 Which component lets current go one way? (a) resistor (b) capacitor (c) diode (d) LED
12. 12.🔺 A current of 1 A flows when 2 V is joined across a resistor. What is its resistance (in ohms)?
13. 13.🧾 A family uses 30 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?
14. 14.⏱️ What does “wait 500 ms” do? (a) blinks 500 times (b) pauses for half a second (c) waits 500 seconds (d) turns the LED off
15. 15.🔢 To run one loop of a plant-watering program, which is the LAST step? (a) compare with the limit (b) read the soil sensor (c) switch the pump on/off (d) wait a few seconds
16. 16.Which of these usually has a microcontroller inside? (a) a spinning top (b) a toy robot (c) a candle (d) a hand pump
17. 17.🔘 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 OFF. Does the bulb glow? (a) No (b) Yes
18. 18.True or false: a line lifted at a gap is the symbol for a switch. (a) False (b) True
19. 19.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 9 hours. How many watt-hours (Wh) are saved?
20. 20.💡 In a series circuit, how many paths does the current have? (a) one (b) one for each bulb (c) none (d) two
21. 21.⏱️ loop forever { LED ON; wait 300 ms; LED OFF; wait 750 ms }
    How many milliseconds does one blink (ON + OFF) take?
22. 22.True or false: “the pump turns on” is the process. (a) False (b) True
23. 23.🌈 A gold fourth band on a resistor means the value may be off by … (a) 25 % (b) 50 % (c) 0 % (d) 5 %
24. 24.True or false: if a wire is cut, the circuit is closed and current flows. (a) False (b) True
25. 25.🔺 A current of 0.2 A flows when 1.6 V is joined across a resistor. What is its resistance (in ohms)?
26. 26.True or false: current is measured in amperes (A). (a) False (b) True
27. 27.Which job needs a buzzer? (a) spin a robot’s wheels (b) beep an alarm (c) show the temperature (d) show a status light
28. 28.💡 Old festival light strings went fully dark when one bulb failed. How were they joined? (a) in series (b) not joined (c) in parallel (d) by Wi-Fi
29. 29.🔘 Which kind of switch flips up or down? (a) a push button (b) a reed switch (c) a tilt switch (d) a toggle switch
30. 30.🔋 On a cell, does “usually the red wire” mean the + end or the − end? (a) − (negative) (b) + (positive)
31. 31.🔢 To plan an electronics project, which comes first: “test it and fix it” or “list inputs and outputs”? (a) test it and fix it (b) list inputs and outputs
32. 32.🔍 Which is the odd one out? (a) touch a fallen wire (b) fly a kite near wires (c) dry your hands first (d) touch a switch when wet
33. 33.🌈 A resistor has the colour bands red, grey, yellow. What is its value in kilo-ohms (kΩ)? =
34. 34.🤖 “if (A AND B)” is true when … (a) only B is true (b) both A and B are true (c) only A is true (d) both are false
35. 35.🤖 if (light < 300) { lamp ON } else { lamp OFF }
    The light sensor reads 443. What happens? (a) lamp ON (b) lamp OFF
36. 36.Which job needs a motor? (a) turn to an exact angle (b) open a gate to 90° (c) show a status light (d) spin a robot’s wheels
37. 37.🔘 A bulb and a cell are joined through 2 switches on 2 side-by-side paths, one switch on each path (parallel). What is the smallest number of switches that must be ON to light the bulb?
38. 38.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
39. 39.Which of these is a good habit? (a) post your live location (b) keep factory passwords (c) share camera links (d) read app permissions
40. 40.⏱️ How many milliseconds is a wait of 1.6 seconds?

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