Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 28 · 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.🔁 Is the circuit closed or open if a cell is taken out? (a) open (b) closed
2. 2.🧾 One “unit” on an electricity bill is … (a) 1 ampere (b) 1 watt (c) 1 kilowatt-hour (kWh) (d) 1 volt
3. 3.🔺 A current of 0.2 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
4. 4.🧭 Which part of a microcontroller board brings power and code? (a) the reset button (b) the voltage regulator (c) the USB port (d) the main chip
5. 5.💡 3 identical bulbs are joined in series with a battery and a closed switch on the main wire. Bulb 3 is taken out of its holder. Does bulb 2 glow? (a) No (b) Yes
6. 6.🧩 Which part changes electrical energy into sound? (a) a buzzer (b) a resistor (c) a diode (d) a capacitor
7. 7.Which of these is true of a parallel circuit? (a) a single current path (b) a break stops every bulb (c) bulbs share the voltage (d) one out, the rest glow
8. 8.Which of these is an insulator? (a) a plastic ruler (b) a brass key (c) a safety pin (d) aluminium foil
9. 9.True or false: a paper strip is a conductor. (a) True (b) False
10. 10.✏️ In a circuit diagram, which part is drawn as a long and a short line? (a) switch (b) wire (c) motor (d) cell
11. 11.🔁 repeat 3 times { repeat 5 times { beep } }
    How many beeps are there?
12. 12.⚡ A device works on 24 V and takes 0.25 A. What is its power (in watts)? =
13. 13.🔺 A current of 25 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
14. 14.⚡ A device works on 3 V and takes 2 A. What is its power (in watts)? =
15. 15.💡 An LED is joined to a 3 V battery through a 220 Ω resistor; its long leg goes to the + side and its short leg to the − side. What happens? (a) may burn out (b) does not light (c) lights up
16. 16.⚡ A 2.25 W device works on 9 V. What current does it take (in amperes)? =
17. 17.💡 What does LED stand for? (a) light energy dial (b) low energy device (c) light-emitting diode (d) large electric dial
18. 18.⚡ Which tiny particles drift along a metal wire to carry the current? (a) water drops (b) dust particles (c) photons (d) electrons
19. 19.True or false: a motor makes things spin. (a) True (b) False
20. 20.🔋 On a cell, does “the shorter symbol line” mean the + end or the − end? (a) − (negative) (b) + (positive)
21. 21.🔺 A 2.5 V supply is joined across a 100 Ω resistor. What current flows (in milliamperes, mA)?
22. 22.True or false: on an LED, the shorter leg is the anode (+). (a) True (b) False
23. 23.Which job needs a light sensor? (a) spot someone walking in (b) switch on with a clap (c) stop a robot near walls (d) open blinds at sunrise
24. 24.Which of these is safe? (a) climb an electric pole (b) open a phone charger (c) touch a switch when wet (d) use small battery cells
25. 25.🔺 A 1 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
26. 26.📏 How many kilowatts (kW) is 3350 W? =
27. 27.🔺 A current of 20 mA flows when 8 V is joined across a resistor. What is its resistance (in ohms)?
28. 28.🔘 A cell and a bulb are joined to 3 side-by-side paths with one switch on each path — A, B and C (parallel). A is OFF, B is OFF and C is ON. Does the bulb glow? (a) Yes (b) No
29. 29.📶 On a 5 V board, a pin set HIGH gives about … (a) 50 V (b) 230 V (c) 5 V (d) 0 V
30. 30.🔍 Which is the odd one out? (a) a buzzer (b) a room heater (c) a rice cooker (d) a toaster
31. 31.True or false: a rubber band is a conductor. (a) True (b) False
32. 32.🤖 if (temperature > 32) { fan ON } else { fan OFF }
    The temperature sensor reads 38 °C. What happens? (a) fan OFF (b) fan ON
33. 33.🗺️ In an input → process → output plan, is “a light level reading” the input, the process or the output? (a) process (b) input (c) output
34. 34.Which of these is not an IoT device? (a) a Wi-Fi weather station (b) a smart energy meter (c) a battery torch (d) an app-controlled bulb
35. 35.True or false: a ceiling fan mainly gives out light. (a) False (b) True
36. 36.Which of these is measured in volts (V)? (a) how much a part resists (b) power (c) energy used each second (d) the push of a cell
37. 37.⏱️ How many milliseconds is a wait of 2.8 seconds?
38. 38.🔺 A current of 0.2 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
39. 39.⚡ What do we call a flow of electric charge through a wire? (a) friction (b) sound (c) electric current (d) a magnet
40. 40.🔦 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 steel coin. Does the bulb glow? (a) Yes (b) No

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