Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 30 · 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.🔐 Why install updates on IoT devices? (a) they fix security holes (b) they delete the Wi-Fi (c) they make it heavier (d) they change the colour
2. 2.🔺 An 18 V supply is joined across a 12 Ω resistor. What current flows (in amperes)? =
3. 3.True or false: a microcontroller uses very little power. (a) True (b) False
4. 4.⚡ A home appliance on the 230 V mains takes 10 A. What is its power (in watts)?
5. 5.🌈 A gold fourth band on a resistor means the value may be off by … (a) 5 % (b) 25 % (c) 0 % (d) 50 %
6. 6.🔋 2 identical 1.5 V cells are joined in series (+ of one cell to − of the next). What is the total voltage (in volts)? =
7. 7.🔘 A cell and a bulb are joined to two side-by-side paths: path 1 has switches A and B one after another, path 2 has switch C. A is ON, B is ON and C is ON. Does the bulb glow? (a) Yes (b) No
8. 8.🔺 A current of 1.5 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
9. 9.🔘 A cell, a bulb and switches A, B, C and D are joined one after another in a single loop (series). A is ON, B is OFF, C is OFF and D is OFF. Does the bulb glow? (a) No (b) Yes
10. 10.Which drawing is the symbol for a switch? (a) two or more cell symbols (b) a line lifted at a gap (c) a plain rectangle (d) a long and a short line
11. 11.🔁 Is the circuit closed or open if the loop is complete? (a) closed (b) open
12. 12.🧮 Adding another resistor in series makes the total resistance … (a) smaller (b) stay the same (c) zero (d) bigger
13. 13.True or false: two or more cell symbols is the symbol for a battery. (a) True (b) False
14. 14.🧭 Which part of a microcontroller board connect sensors and LEDs? (a) the main chip (b) the pins (c) the USB port (d) the power LED
15. 15.🤖 if (light < 500) { lamp ON } else { lamp OFF }
    The light sensor reads 494. What happens? (a) lamp ON (b) lamp OFF
16. 16.Which of these mainly gives out light? (a) a water heater (b) a doorbell (c) a school bell (d) a street light
17. 17.🔘 When a switch is ON, the circuit is … (a) broken (b) closed (c) open (d) cut
18. 18.⚡ Which formula gives electric power? (a) P = V + I (b) P = I ÷ V (c) P = V ÷ I (d) P = V × I
19. 19.🔺 In the V-I-R triangle, how do we find R? (a) R = I ÷ V (b) R = V × I (c) R = V + I (d) R = V ÷ I
20. 20.⚡ What does a water heater mainly change electricity into? (a) heat (b) movement (c) light (d) sound
21. 21.🔍 Which is the odd one out? (a) tap unknown app links (b) share camera links (c) reuse one password (d) cover unused cameras
22. 22.💡 6 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 4 glow? (a) Yes (b) No
23. 23.⏱️ How many milliseconds are in 1 second? (a) 60 (b) 1000 (c) 10 (d) 100
24. 24.🔍 Which is the odd one out? (a) a torch (b) a toaster (c) a water heater (d) an electric kettle
25. 25.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) both of them (b) only one (c) none (d) it does not matter
26. 26.⚡ A device works on 24 V and takes 1 A. What is its power (in watts)? =
27. 27.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
28. 28.🔺 A current of 50 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
29. 29.🧩 Which component makes things spin? (a) LDR (b) motor (c) potentiometer (d) resistor
30. 30.🔁 count = 2
    while (count < 11) { count = count + 3 }
    How many times does the loop run?
31. 31.🔺 A current of 20 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
32. 32.💡 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)?
33. 33.🔗 Series or parallel circuit: “many paths for current”? (a) parallel (b) series
34. 34.🤖 if (light < 400 AND motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 50 and motion is not detected (false). What happens? (a) porch lamp ON (b) porch lamp OFF
35. 35.🔺 In the V-I-R triangle, how do we find V? (a) V = I × R (b) V = I + R (c) V = R ÷ I (d) V = I ÷ R
36. 36.🔘 Switch A is on the main wire next to the cell and the bulb; then the wire splits into two side-by-side paths, one with switch B and one with switch C. A is ON, B is ON and C is OFF. Does the bulb glow? (a) No (b) Yes
37. 37.📶 On a 5 V board, a pin set HIGH gives about … (a) 0 V (b) 50 V (c) 230 V (d) 5 V
38. 38.💡 2 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 2 is taken out of its holder. How many bulbs glow?
39. 39.🔺 A 1.5 V supply is joined across a 3 Ω resistor. What current flows (in amperes)? =
40. 40.💡 An LED (with its resistor) is on pin 8. All pins start LOW. The program runs once:
    set pin 7 LOW
    set pin 8 HIGH
    set pin 7 HIGH
    set pin 7 HIGH
    set pin 8 LOW
    Is the LED ON or OFF at the end? (a) ON (b) OFF

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