Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 271 · 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 a series circuit, how many paths does the current have? (a) one for each bulb (b) none (c) two (d) one
2. 2.🔺 A current of 20 mA flows through a 470 Ω resistor. What is the voltage across it (in volts)? =
3. 3.True or false: to touch a fallen wire is safe. (a) False (b) True
4. 4.🔋 On a cell, does “the end with a bump” mean the + end or the − end? (a) − (negative) (b) + (positive)
5. 5.Which job needs a gas sensor? (a) spot someone walking in (b) warn of a gas leak (c) switch on with a clap (d) water a dry plant
6. 6.🔍 Which sensor would you use to water a dry plant? (a) a rain sensor (b) a motion sensor (c) a soil moisture sensor (d) a sound sensor
7. 7.Which of these saves electricity? (a) leave the TV on standby (b) leave fridge door open (c) unplug idle chargers (d) run fans in empty rooms
8. 8.🌐 Is a pencil sharpener an IoT device? (a) not an IoT device (b) an IoT device
9. 9.🧮 Two equal 200 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
10. 10.🤖 if (light < 300 OR motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 270 and motion is detected (true). What happens? (a) porch lamp ON (b) porch lamp OFF
11. 11.True or false: an exhaust fan mainly makes movement. (a) False (b) True
12. 12.🔐 Is it a good or a risky habit to accept every permission? (a) risky habit (b) good habit
13. 13.🔢 To get a sensor reading onto a phone, which is the FIRST step? (a) the cloud stores it (b) the sensor measures (c) the app shows it (d) the board reads it
14. 14.🧮 A 2.4 V battery is joined to 4 Ω and 8 Ω resistors in series. What current flows (in amperes)? =
15. 15.⚡ A home appliance on the 230 V mains takes 1 A. What is its power (in watts)?
16. 16.🔍 Which is the odd one out? (a) turn off unused gadgets (b) tap unknown app links (c) log out of shared phones (d) set a strong password
17. 17.🔁 total = 0
    for i = 1 to 11 { total = total + i }
    What is total at the end?
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 of these is the input? (a) count button presses (b) the fan starts (c) the pump turns on (d) a motion sensor signal
20. 20.🔌 Is a steel spoon a conductor or an insulator? (a) an insulator (b) a conductor
21. 21.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
22. 22.📏 Which unit measures the flow of charge? (a) ohm (Ω) (b) ampere (A) (c) volt (V) (d) watt (W)
23. 23.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. Does the bulb glow? (a) Yes (b) No
24. 24.🗺️ In “input → process → output”, which part is the decision the program makes? (a) the output (b) the process (c) the input (d) the battery
25. 25.🔋 5 identical 2 V cells are joined side by side in parallel (all + ends together, all − ends together). What is the voltage across them (in volts)? =
26. 26.🤖 if (light < 200) { lamp ON } else { lamp OFF }
    The light sensor reads 212. What happens? (a) lamp ON (b) lamp OFF
27. 27.⚡ A device works on 1.5 V and takes 0.5 A. What is its power (in watts)? =
28. 28.🤖 if (distance < 30) { buzzer beeps } else { buzzer is silent }
    The distance sensor reads 38 cm. What happens? (a) buzzer is silent (b) buzzer beeps
29. 29.Which of these is safe? (a) dry your hands first (b) touch a switch when wet (c) poke things in a socket (d) open a phone charger
30. 30.🧮 Resistors of 20 Ω, 220 Ω, 470 Ω and 330 Ω are joined in series. What is the total resistance (in ohms)?
31. 31.🔘 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 OFF, B is OFF and C is OFF. Does the bulb glow? (a) Yes (b) No
32. 32.🔘 Which kind of switch works only while pressed? (a) a slide switch (b) a reed switch (c) a push button (d) a tilt switch
33. 33.🔺 A current of 1 A flows when 2 V is joined across a resistor. What is its resistance (in ohms)?
34. 34.🔺 A current of 2.5 A flows when 50 V is joined across a resistor. What is its resistance (in ohms)?
35. 35.⏱️ What does “wait 500 ms” do? (a) pauses for half a second (b) turns the LED off (c) waits 500 seconds (d) blinks 500 times
36. 36.🧩 Which component stores a little charge? (a) resistor (b) capacitor (c) LED (d) motor
37. 37.🔍 Which is the odd one out? (a) a ceiling fan (b) a mixer grinder (c) a table fan (d) a doorbell
38. 38.💡 An LED is joined to a 5 V battery through a 220 Ω resistor; its long leg goes to the + side and its short leg to the − side. What happens? (a) does not light (b) may burn out (c) lights up
39. 39.🔍 Which is the odd one out? (a) an app-controlled bulb (b) a paper calendar (c) a plain wall switch (d) a battery torch
40. 40.True or false: if a cell is taken out, the circuit is closed and current flows. (a) False (b) True

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