Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 985 · 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 is the odd one out? (a) a temperature sensor (b) a servo motor (c) a turning knob (d) a motion sensor
2. 2.True or false: “used in house wiring” is true of a parallel circuit. (a) False (b) True
3. 3.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 7 hours. How many watt-hours (Wh) are saved?
4. 4.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
5. 5.⚠️ Which power source should children use for electronics projects? (a) an inverter socket (b) a small battery pack (c) a mains extension board (d) a wall socket
6. 6.🤖 How does a new program get onto a microcontroller board? (a) uploaded over USB (b) sent by sound (c) drawn with a pen (d) typed on the chip
7. 7.True or false: if a wire is cut, the circuit is closed and current flows. (a) True (b) False
8. 8.Which job needs a display? (a) show a status light (b) spin a robot’s wheels (c) turn to an exact angle (d) show the temperature
9. 9.📏 In the water-pipe picture of a circuit, resistance is like … (a) a narrow pipe (b) a bigger tank (c) the water pressure (d) the flow of water
10. 10.🌈 A resistor has the colour bands green, red, yellow. What is its value in kilo-ohms (kΩ)? =
11. 11.True or false: a candle usually has a microcontroller inside. (a) True (b) False
12. 12.💡 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
13. 13.🔁 total = 0
    for i = 1 to 9 { total = total + i }
    What is total at the end?
14. 14.True or false: “each gets the full volts” is true of a series circuit. (a) True (b) False
15. 15.⚠️ Is it safe to take cells out after use? (a) not safe (b) safe
16. 16.🤖 if (temperature > 36) { show “Hot” } else if (temperature > 22) { show “Warm” } else { show “Cool” }
    The temperature is 12 °C. What is shown? (a) Hot (b) Warm (c) Cool
17. 17.⚡ What does a ceiling fan mainly change electricity into? (a) movement (b) sound (c) light (d) heat
18. 18.🔍 Which is the odd one out? (a) a brass key (b) a steel spoon (c) a copper wire (d) a cotton thread
19. 19.🤖 if (sound > 60) { red LED ON } else { green LED ON }
    The sound sensor reads 55. What happens? (a) red LED ON (b) green LED ON
20. 20.💡 Why does an LED need a resistor in series? (a) to make it brighter (b) to store charge (c) to change its colour (d) to limit the current
21. 21.🔋 How many volts does one ordinary torch cell give? (a) 15 V (b) 0.5 V (c) 230 V (d) 1.5 V
22. 22.🔺 A current of 3 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
23. 23.True or false: to ignore update messages is a risky habit. (a) True (b) False
24. 24.💡 An LED is joined to a 6 V battery through a 330 Ω resistor; the leg next to the flat edge of its rim goes to the − side. What happens? (a) lights up (b) does not light (c) may burn out
25. 25.🔗 Series or parallel circuit: “own switch for each bulb”? (a) series (b) parallel
26. 26.🧩 Which component glows using little power? (a) buzzer (b) LDR (c) potentiometer (d) LED
27. 27.🔦 A circuit has a new cell, a good bulb and a switch that is ON. One wire has come loose from the cell. A gap in one wire is bridged by a dry cork. Does the bulb glow? (a) No (b) Yes
28. 28.🔍 Which is the odd one out? (a) an LED lamp (b) a doorbell (c) a loudspeaker (d) a siren
29. 29.⚠️ What protects home wiring by melting or tripping when too much current flows? (a) a fuse or MCB (b) a long wire (c) a plug top (d) a bulb
30. 30.🌐 A weather station sends one reading every 30 seconds. How many readings does it send in 7 minutes?
31. 31.True or false: two equal parallel lines is the symbol for a voltmeter. (a) True (b) False
32. 32.🔁 What does “count = count + 1” do? (a) takes 1 away (b) prints 1 (c) sets count to 1 (d) adds 1 to count
33. 33.💡 An LED (with its resistor) is on pin 8. All pins start LOW. The program runs once:
    set pin 8 LOW
    set pin 7 LOW
    set pin 8 LOW
    Is the LED ON or OFF at the end? (a) OFF (b) ON
34. 34.⚡ What does an LED lamp mainly change electricity into? (a) light (b) movement (c) sound (d) heat
35. 35.⚡ A 1.5 W device works on 1.5 V. What current does it take (in amperes)? =
36. 36.🔺 A current of 2.5 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
37. 37.🧾 A family uses 170 units of electricity in a month and each unit costs ₹5. What is the bill (in ₹)?
38. 38.🔋 What is a battery? (a) a switch with a lid (b) a kind of bulb (c) two or more cells joined (d) one single wire
39. 39.⏱️ loop forever { LED ON; wait 50 ms; LED OFF; wait 450 ms }
    How many times does the LED blink in 9 seconds?
40. 40.🔺 A current of 20 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =

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