Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 648 · 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.🧭 Which part of a microcontroller board connect sensors and LEDs? (a) the main chip (b) the power LED (c) the USB port (d) the pins
2. 2.💡 Old festival light strings went fully dark when one bulb failed. How were they joined? (a) by Wi-Fi (b) in parallel (c) not joined (d) in series
3. 3.🧮 Resistors of 220 Ω and 68 Ω are joined in series. What is the total resistance (in ohms)?
4. 4.⚠️ Someone is getting a shock and is still touching a wire. What should you do? (a) wait and watch (b) shout for an adult (c) pull them by the hand (d) pour water on them
5. 5.🔋 On a cell, does “the shorter symbol line” mean the + end or the − end? (a) + (positive) (b) − (negative)
6. 6.🔁 x = 5
   repeat 5 times { x = x × 2 }
   What is x at the end?
7. 7.🌈 In the resistor colour code, which number does brown stand for?
8. 8.🔺 A current of 0.1 A flows when 0.3 V is joined across a resistor. What is its resistance (in ohms)?
9. 9.💡 What happens if an LED is put in backwards? (a) it does not light (b) it lights brighter (c) it makes a sound (d) it changes colour
10. 10.🤖 if (light < 200 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 OFF (b) porch lamp ON
11. 11.True or false: a loudspeaker mainly makes sound. (a) False (b) True
12. 12.True or false: to take cells out after use is not safe. (a) False (b) True
13. 13.🤖 if (distance < 15) { buzzer beeps } else { buzzer is silent }
    The distance sensor reads 18 cm. What happens? (a) buzzer beeps (b) buzzer is silent
14. 14.🔺 A current of 0.1 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
15. 15.🔺 A current of 20 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
16. 16.🌈 Which band is read first on a resistor? (a) the widest gap (b) the gold band (c) the one nearest an end (d) any band
17. 17.🧮 Two equal 50 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
18. 18.🔺 A current of 3 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
19. 19.What does a tilt switch do? (a) works only while pressed (b) stays where you flip it (c) closes when tipped over (d) flips up or down
20. 20.Which of these is a risky habit? (a) reuse one password (b) set up with a parent (c) set a strong password (d) install software updates
21. 21.Which of these has no microcontroller inside? (a) a toy robot (b) a hand pump (c) a digital thermometer (d) a TV remote
22. 22.🔗 Series or parallel circuit: “each gets the full volts”? (a) parallel (b) series
23. 23.🧮 Five equal 125 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
24. 24.🔁 x = 4
    repeat 5 times { x = x × 2 }
    What is x at the end?
25. 25.🌈 A resistor has the colour bands white, violet, orange. What is its value (in ohms)?
26. 26.🧮 Adding another resistor in series makes the total resistance … (a) zero (b) smaller (c) stay the same (d) bigger
27. 27.True or false: an iron nail is an insulator. (a) False (b) True
28. 28.🔺 A 2 V supply is joined across a 200 Ω resistor. What current flows (in milliamperes, mA)?
29. 29.🔁 What does “count = count + 1” do? (a) prints 1 (b) takes 1 away (c) adds 1 to count (d) sets count to 1
30. 30.⚙️ What is an actuator? (a) a sensor (b) a program (c) a battery (d) an output that acts
31. 31.⚡ A solar panel changes which kind of energy into electricity? (a) wind energy (b) light energy (c) chemical energy (d) sound energy
32. 32.Which of these wastes electricity? (a) use daylight to read (b) use LED lamps (c) leave fridge door open (d) set the AC to 24 °C
33. 33.🌈 A resistor has the colour bands yellow, green, black. What is its value (in ohms)?
34. 34.Which of these means the circuit is open? (a) the switch is ON (b) the loop is complete (c) a wire has come loose (d) all wires are joined
35. 35.⚠️ Is it safe to climb an electric pole? (a) not safe (b) safe
36. 36.🔺 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
37. 37.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
38. 38.🔺 In the V-I-R triangle, how do we find R? (a) R = V × I (b) R = V + I (c) R = I ÷ V (d) R = V ÷ I
39. 39.🔁 What must there be for a current to flow? (a) a complete loop (b) one loose end (c) a broken path (d) a plastic gap
40. 40.True or false: to close the fridge quickly wastes electricity. (a) True (b) False

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