Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 20 · 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.🔺 In the V-I-R triangle, how do we find V? (a) V = I × R (b) V = I ÷ R (c) V = I + R (d) V = R ÷ I
2. 2.🔺 A current of 20 mA flows when 6.6 V is joined across a resistor. What is its resistance (in ohms)?
3. 3.🔺 A current of 0.1 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
4. 4.True or false: “a single current path” is true of a parallel circuit. (a) True (b) False
5. 5.🤖 if (light < 400 OR motion) { porch lamp ON } else { porch lamp OFF }
   The light reading is 180 and motion is not detected (false). What happens? (a) porch lamp ON (b) porch lamp OFF
6. 6.🌐 A soil sensor sends a reading to an app every 15 minutes. How many readings arrive in 1 hour?
7. 7.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 12000 Ω resistor? (a) brown-red-orange (b) red-brown-orange (c) brown-red-red (d) brown-red-yellow
8. 8.⚠️ Is it safe to climb an electric pole? (a) safe (b) not safe
9. 9.🔺 In the V-I-R triangle, how do we find R? (a) R = V × I (b) R = I ÷ V (c) R = V + I (d) R = V ÷ I
10. 10.🔺 A current of 3 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
11. 11.🌈 A resistor has the colour bands violet, black, red. What is its value in kilo-ohms (kΩ)? =
12. 12.✏️ In a circuit diagram, which part is drawn as a circle with an X in it? (a) cell (b) wire (c) motor (d) bulb
13. 13.Which of these means the circuit is closed? (a) all wires are joined (b) the bulb is unscrewed (c) a cell is taken out (d) a wire has come loose
14. 14.Which job is done by the voltage regulator? (a) restarts the program (b) keeps the voltage steady (c) runs the program (d) brings power and code
15. 15.🌈 A resistor has the colour bands violet, brown, red. What is its value in kilo-ohms (kΩ)? =
16. 16.🌐 Is an app-controlled bulb an IoT device? (a) not an IoT device (b) an IoT device
17. 17.🌈 A resistor has the colour bands red, brown, orange. What is its value (in ohms)?
18. 18.🔍 Which is the odd one out? (a) an electric kettle (b) a rice cooker (c) an electric iron (d) a tube light
19. 19.🔁 count = 4
    repeat 3 times { count = count + 5 }
    What is count at the end?
20. 20.🔍 For a microcontroller, is a sensor an input or an output? (a) a power source (b) an output (c) a fuse (d) an input
21. 21.🔁 What does a variable do in a program? (a) blinks an LED (b) measures light (c) joins two wires (d) stores a value
22. 22.🔐 Why install updates on IoT devices? (a) they change the colour (b) they make it heavier (c) they fix security holes (d) they delete the Wi-Fi
23. 23.✏️ In a circuit diagram, wires are usually drawn as … (a) dotted circles (b) straight lines (c) wavy lines (d) little stars
24. 24.Which job is done by the power LED? (a) runs the program (b) brings power and code (c) restarts the program (d) shows the board is on
25. 25.🗺️ In “input → process → output”, which part is the decision the program makes? (a) the input (b) the output (c) the battery (d) the process
26. 26.Which of these is true of a series circuit? (a) many paths for current (b) each gets the full volts (c) own switch for each bulb (d) a break stops every bulb
27. 27.🔘 Which kind of switch closes near a magnet? (a) a tilt switch (b) a slide switch (c) a reed switch (d) a toggle switch
28. 28.🧾 A 40 W filament bulb is swapped for a 6 W LED lamp that gives about the same light. Both would run for 7 hours. How many watt-hours (Wh) are saved?
29. 29.💡 3 identical bulbs are joined in series with a 3 V battery (ideal wires). How many volts does each bulb get? =
30. 30.🌈 A resistor has the colour bands orange, red, red. What is its value in kilo-ohms (kΩ)? =
31. 31.💡 A red LED (it uses 2 V) is joined with a 200 Ω resistor to a 3 V supply. What current flows (in mA)?
32. 32.🔋 Cells joined + to − in a row (series) give … (a) the same voltage (b) a bigger voltage (c) no voltage (d) a smaller voltage
33. 33.💡 An LED (with its resistor) is on pin 8. All pins start LOW. The program runs once:
    set pin 8 HIGH
    set pin 8 HIGH
    Is the LED ON or OFF at the end? (a) ON (b) OFF
34. 34.🌐 Each reading a sensor sends is 25 bytes. How many bytes do 170 readings take?
35. 35.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a brass key. Does the bulb glow? (a) No (b) Yes
36. 36.⚙️ What is an actuator? (a) an output that acts (b) a program (c) a sensor (d) a battery
37. 37.🔺 A 1.2 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
38. 38.🔁 x = 4
    repeat 1 time { x = x × 2 }
    What is x at the end?
39. 39.🧾 One “unit” on an electricity bill is … (a) 1 watt (b) 1 kilowatt-hour (kWh) (c) 1 volt (d) 1 ampere
40. 40.⚡ A solar panel changes which kind of energy into electricity? (a) sound energy (b) light energy (c) chemical energy (d) wind energy

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