Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 248 · 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.True or false: a small empty box is the symbol for a resistor. (a) False (b) True
2. 2.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the glass (b) the filament (c) the switch (d) the base
3. 3.🔺 A current of 2 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
4. 4.📏 How many kilowatts (kW) is 3450 W? =
5. 5.🧩 Which component senses how bright it is? (a) capacitor (b) LDR (c) potentiometer (d) transistor
6. 6.💡 Why is house wiring done in parallel? (a) each gets full voltage (b) to save copper only (c) to make bulbs dim (d) so all go off together
7. 7.Which of these has no microcontroller inside? (a) a washing machine (b) a TV remote (c) a digital thermometer (d) a hand pump
8. 8.🔺 A current of 40 mA flows through a 250 Ω resistor. What is the voltage across it (in volts)? =
9. 9.⚠️ Is it safe to use small battery cells? (a) safe (b) not safe
10. 10.🤖 if (light < 400 AND motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 160 and motion is not detected (false). What happens? (a) porch lamp ON (b) porch lamp OFF
11. 11.Which of these is measured in watts (W)? (a) resistance (b) how much a part resists (c) power (d) voltage
12. 12.🔍 Which is the odd one out? (a) an exhaust fan (b) an electric drill (c) a night lamp (d) a ceiling fan
13. 13.True or false: on an LED, the round-side leg is the cathode (−). (a) False (b) True
14. 14.True or false: “a soil moisture reading” is the input. (a) False (b) True
15. 15.🔺 A 0.4 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
16. 16.🌐 How does a home IoT device usually send its data to the app? (a) over Wi-Fi (b) through a candle (c) by post (d) by shouting
17. 17.🧾 A 75 W filament bulb is swapped for a 12 W LED lamp that gives about the same light. Both would run for 8 hours. How many watt-hours (Wh) are saved?
18. 18.🔺 In the V-I-R triangle, how do we find V? (a) V = R ÷ I (b) V = I × R (c) V = I ÷ R (d) V = I + R
19. 19.🔍 Which is the odd one out? (a) poke things in a socket (b) use a cable with cuts (c) dry your hands first (d) open a phone charger
20. 20.🔺 A current of 0.1 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
21. 21.🧭 Which part of a microcontroller board restarts the program? (a) the reset button (b) the power LED (c) the USB port (d) the main chip
22. 22.True or false: if the loop is complete, the circuit is closed and current flows. (a) False (b) True
23. 23.True or false: the push of a cell is measured in ohms (Ω). (a) True (b) False
24. 24.🧮 A 3 V battery is joined to 6 Ω and 6 Ω resistors in series. What current flows (in amperes)? =
25. 25.🔘 A bulb and a cell are joined through 5 switches one after another in a single loop (series). What is the smallest number of switches that must be ON to light the bulb?
26. 26.🔍 Which is the odd one out? (a) a buzzer beeps (b) the pump turns on (c) an LED lights up (d) a motion sensor signal
27. 27.🧮 A 47 Ω resistor is joined in series with two equal 200 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
28. 28.💡 A battery lights 5 identical bulbs joined in series. One more identical bulb is added in series. How do the bulbs glow now? (a) brighter (b) dimmer (c) the same
29. 29.🔐 A smart speaker is always listening for its wake word. What is a sensible habit? (a) mute it when not in use (b) tell it your passwords (c) let strangers use it (d) put it in the bathroom
30. 30.📏 How many ohms (Ω) is 4.7 kΩ?
31. 31.True or false: to close the fridge quickly saves electricity. (a) True (b) False
32. 32.✏️ In a circuit diagram, which part is drawn as a circle with M inside? (a) motor (b) ammeter (c) battery (d) cell
33. 33.🔋 On a cell, does “the shorter symbol line” mean the + end or the − end? (a) − (negative) (b) + (positive)
34. 34.⚠️ Someone is getting a shock and is still touching a wire. What should you do? (a) pour water on them (b) shout for an adult (c) wait and watch (d) pull them by the hand
35. 35.Which of these is true of a parallel circuit? (a) one bulb out, all go out (b) a single current path (c) used in house wiring (d) bulbs share the voltage
36. 36.🧩 Which component smooths a wobbly supply? (a) LDR (b) thermistor (c) capacitor (d) resistor
37. 37.Which job needs a display? (a) spin a robot’s wheels (b) turn to an exact angle (c) show the temperature (d) move water to plants
38. 38.True or false: power is measured in watts (W). (a) True (b) False
39. 39.🧮 Resistors of 330 Ω, 150 Ω and 33 Ω are joined in series. What is the total resistance (in ohms)?
40. 40.True or false: a thermistor smooths a wobbly supply. (a) False (b) True

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