Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 54 · 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 woollen thread (b) a rubber eraser (c) an iron nail (d) a plastic straw
2. 2.🔺 In the V-I-R triangle, how do we find I? (a) I = V ÷ R (b) I = V + R (c) I = V × R (d) I = R ÷ V
3. 3.⏱️ loop forever { LED ON; wait 150 ms; LED OFF; wait 50 ms }
   How many times does the LED blink in 8 seconds?
4. 4.Which of these mainly gives out light? (a) a water heater (b) a toaster (c) a rice cooker (d) a night lamp
5. 5.Which of these is a risky habit? (a) keep factory passwords (b) set a strong password (c) turn off unused gadgets (d) install software updates
6. 6.🔋 Does a wind turbine give electricity or use electricity? (a) uses electricity (b) gives electricity
7. 7.🧮 A 68 Ω resistor is joined in series with two equal 10 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
8. 8.🔁 count = 1
   repeat 6 times { count = count + 8 }
   What is count at the end?
9. 9.What does a reed switch do? (a) slides side to side (b) closes near a magnet (c) springs back when let go (d) closes when tipped over
10. 10.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
11. 11.True or false: a table fan mainly makes movement. (a) True (b) False
12. 12.⚙️ Which actuator would you use to turn to an exact angle? (a) a servo motor (b) an LED (c) a pump (d) a motor
13. 13.🤖 if (light < 300 AND motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 110 and motion is not detected (false). What happens? (a) porch lamp OFF (b) porch lamp ON
14. 14.True or false: a small empty box is the symbol for a resistor. (a) False (b) True
15. 15.🧮 Adding another resistor in series makes the total resistance … (a) bigger (b) stay the same (c) zero (d) smaller
16. 16.⚠️ Is it safe to throw cells in a fire? (a) safe (b) not safe
17. 17.🔍 Which is the odd one out? (a) switch off empty rooms (b) use LED lamps (c) leave the TV on standby (d) close the fridge quickly
18. 18.🔌 Which metal is used for most electric wires at home? (a) plastic (b) rubber (c) copper (d) glass
19. 19.⚡ A home appliance on the 230 V mains takes 4 A. What is its power (in watts)?
20. 20.⚠️ Is it safe to fly a kite near wires? (a) not safe (b) safe
21. 21.🧭 Which part of a microcontroller board connect sensors and LEDs? (a) the reset button (b) the pins (c) the main chip (d) the power LED
22. 22.🔋 A 3 V battery and two 1.5 V cells are joined in series, all facing the same way. What is the total voltage (in volts)? =
23. 23.🔺 A current of 0.2 A flows when 4 V is joined across a resistor. What is its resistance (in ohms)?
24. 24.🔋 A 6 V battery and four 1.5 V cells are joined in series, all facing the same way. What is the total voltage (in volts)? =
25. 25.🔘 Two switches are in parallel (side by side). When does the bulb glow? (a) never (b) when either is ON (c) only when both are ON (d) only when both are OFF
26. 26.Which of these is not an IoT device? (a) a battery torch (b) a Wi-Fi doorbell camera (c) a Wi-Fi smart plug (d) a smart energy meter
27. 27.🧩 Which component blows if current is high? (a) LED (b) transistor (c) fuse (d) resistor
28. 28.🔢 To get a sensor reading onto a phone, what comes right after “it is sent by Wi-Fi”? (a) the sensor measures (b) the app shows it (c) the board reads it (d) the cloud stores it
29. 29.🔋 Cells joined + to − in a row (series) give … (a) no voltage (b) a bigger voltage (c) the same voltage (d) a smaller voltage
30. 30.🔺 A 20 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
31. 31.🤖 if (temperature > 32) { show “Hot” } else if (temperature > 26) { show “Warm” } else { show “Cool” }
    The temperature is 21 °C. What is shown? (a) Hot (b) Warm (c) Cool
32. 32.⚡ A 12 W device works on 24 V. What current does it take (in amperes)? =
33. 33.True or false: a resistor turns a fan or wheels. (a) True (b) False
34. 34.🔁 repeat 2 times { repeat 2 times { beep } }
    How many beeps are there?
35. 35.🔋 8 identical 1.5 V cells are joined in series, but one of them is put in the wrong way round. What is the total voltage now (in volts)? =
36. 36.📏 In the water-pipe picture of a circuit, current is like … (a) the water pressure (b) the flow of water (c) a narrow pipe (d) the pipe colour
37. 37.Which of these is an insulator? (a) a steel spoon (b) a graphite rod (c) aluminium foil (d) a rubber eraser
38. 38.🔦 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 brass key. Does the bulb glow? (a) Yes (b) No
39. 39.🔌 Why are electric wires covered in plastic? (a) to make them heavy (b) plastic is an insulator (c) plastic is a conductor (d) plastic makes current
40. 40.True or false: if a wire is cut, the circuit is closed and current flows. (a) False (b) True

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