Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 774 · 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 2.75 V supply. What current flows (in mA)?
2. 2.True or false: power is measured in watts (W). (a) False (b) True
3. 3.🔋 What should you do with used-up cells? (a) bury them in soil (b) cut them open (c) throw them in a fire (d) give them for recycling
4. 4.True or false: “one bulb out, all go out” is true of a parallel circuit. (a) False (b) True
5. 5.Which of these mainly makes sound? (a) a water heater (b) an LED lamp (c) a mixer grinder (d) a siren
6. 6.🔋 On a cell, does “usually the black wire” mean the + end or the − end? (a) − (negative) (b) + (positive)
7. 7.🔗 Series or parallel circuit: “a break stops every bulb”? (a) parallel (b) series
8. 8.🤖 Microcontroller or laptop: which one uses very little power? (a) laptop (b) microcontroller
9. 9.🔁 total = 0
   for i = 1 to 6 { total = total + i }
   What is total at the end?
10. 10.⚠️ About how many volts do home sockets in India supply? (a) 12 V (b) 9 V (c) 230 V (d) 1.5 V
11. 11.🔁 count = 5
    while (count < 20) { count = count + 5 }
    How many times does the loop run?
12. 12.🔋 Does a battery give electricity or use electricity? (a) uses electricity (b) gives electricity
13. 13.🔺 A current of 0.1 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
14. 14.True or false: to share the Wi-Fi key is a risky habit. (a) True (b) False
15. 15.⚡ What does a toaster mainly change electricity into? (a) heat (b) movement (c) sound (d) light
16. 16.Which of these is a conductor? (a) a woollen thread (b) a safety pin (c) a rubber band (d) a paper strip
17. 17.Which job needs an LED? (a) turn to an exact angle (b) spin a robot’s wheels (c) show a status light (d) show the temperature
18. 18.🔺 A current of 2.5 A flows when 12.5 V is joined across a resistor. What is its resistance (in ohms)?
19. 19.🔋 5 identical 1.5 V cells are joined in series, but one of them is put in the wrong way round. What is the total voltage now (in volts)? =
20. 20.True or false: to install software updates is a risky habit. (a) True (b) False
21. 21.🤖 In “if (temp > 30)”, what runs when temp is exactly 30? (a) the else part (b) neither part (c) both parts (d) the if part
22. 22.💡 Why is house wiring done in parallel? (a) so all go off together (b) each gets full voltage (c) to make bulbs dim (d) to save copper only
23. 23.🔘 A cell, a bulb and switches A and B are joined one after another in a single loop (series). A is OFF and B is OFF. Does the bulb glow? (a) No (b) Yes
24. 24.🌐 Each reading a sensor sends is 20 bytes. How many bytes do 60 readings take?
25. 25.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
26. 26.Which of these mainly gives out light? (a) an exhaust fan (b) a water heater (c) a traffic signal (d) a siren
27. 27.⚡ What does a traffic signal mainly change electricity into? (a) movement (b) sound (c) light (d) heat
28. 28.Which of these mainly makes sound? (a) a rice cooker (b) a ceiling fan (c) a mixer grinder (d) a doorbell
29. 29.True or false: “one bulb out, all go out” is true of a series circuit. (a) False (b) True
30. 30.True or false: on an LED, the leg by the flat edge is the cathode (−). (a) False (b) True
31. 31.🧮 Adding another resistor in series makes the total resistance … (a) smaller (b) bigger (c) zero (d) stay the same
32. 32.✏️ In a circuit diagram, which part is drawn as a circle with A inside? (a) diode (b) ammeter (c) LED (d) battery
33. 33.⚡ What does an LED lamp mainly change electricity into? (a) sound (b) movement (c) heat (d) light
34. 34.True or false: a microcontroller needs much more power. (a) True (b) False
35. 35.Which of these means the circuit is closed? (a) a wire has come loose (b) a cell is taken out (c) the bulb is unscrewed (d) the loop is complete
36. 36.📏 How many milliamperes (mA) make 1 ampere? (a) 10 (b) 60 (c) 100 (d) 1000
37. 37.True or false: “check if temp > 30” is the input. (a) False (b) True
38. 38.⏱️ loop forever { LED ON; wait 50 ms; LED OFF; wait 550 ms }
    How many milliseconds does one blink (ON + OFF) take?
39. 39.🔺 A current of 0.5 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
40. 40.🔁 What do we call a circuit with a break in it? (a) a series circuit (b) a full circuit (c) an open circuit (d) a closed circuit

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