Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 140 · 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.🔺 A current of 2.5 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
2. 2.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
3. 3.🔘 Which kind of switch works only while pressed? (a) a toggle switch (b) a slide switch (c) a tilt switch (d) a push button
4. 4.Which of these gives us electricity? (a) an air conditioner (b) a washing machine (c) a solar panel (d) a refrigerator
5. 5.💡 3 identical bulbs are joined in parallel across a 12 V battery (ideal wires). How many volts does each bulb get? =
6. 6.🔺 A current of 25 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
7. 7.🔌 Is an iron nail a conductor or an insulator? (a) an insulator (b) a conductor
8. 8.💡 In a series circuit, how many paths does the current have? (a) none (b) one for each bulb (c) one (d) two
9. 9.🔁 Is the circuit closed or open if a cell is taken out? (a) closed (b) open
10. 10.🔍 Which sensor would you use to keep an incubator warm? (a) a gas sensor (b) a light sensor (c) a soil moisture sensor (d) a temperature sensor
11. 11.True or false: to throw cells in a fire is safe. (a) True (b) False
12. 12.⚠️ Is it safe to climb an electric pole? (a) not safe (b) safe
13. 13.True or false: on an LED, the longer leg is the cathode (−). (a) False (b) True
14. 14.True or false: on an LED, the shorter leg is the cathode (−). (a) False (b) True
15. 15.🔌 Is a sound sensor an input or an output for a microcontroller? (a) output (b) input
16. 16.True or false: a fuse blows if current is high. (a) True (b) False
17. 17.True or false: a line lifted at a gap is the symbol for a cell. (a) False (b) True
18. 18.Which of these is not safe? (a) use a cable with cuts (b) dry your hands first (c) take cells out after use (d) stay away from pylons
19. 19.Which of these means the circuit is open? (a) all wires are joined (b) a wire has come loose (c) the loop is complete (d) the switch is ON
20. 20.💡 4 identical bulbs are joined in parallel (each on its own side-by-side path) with a battery and a closed switch on the main wire. Bulb 4 is taken out of its holder. Does bulb 2 glow? (a) Yes (b) No
21. 21.Which drawing is the symbol for a junction? (a) a dot where wires meet (b) two or more cell symbols (c) a plain rectangle (d) a circle with M inside
22. 22.🤖 In “if (temp > 30)”, what runs when temp is exactly 30? (a) neither part (b) the else part (c) both parts (d) the if part
23. 23.🔍 Which is the odd one out? (a) share camera links (b) share the Wi-Fi key (c) set up with a parent (d) tap unknown app links
24. 24.🔺 A 13.2 V supply is joined across a 330 Ω resistor. What current flows (in milliamperes, mA)?
25. 25.🧩 Which component makes things spin? (a) thermistor (b) motor (c) LED (d) resistor
26. 26.Which of these is not safe? (a) dry your hands first (b) climb an electric pole (c) take cells out after use (d) stay away from pylons
27. 27.🧩 Which component smooths a wobbly supply? (a) LDR (b) LED (c) thermistor (d) capacitor
28. 28.🧮 A 470 Ω resistor is joined in series with two equal 220 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
29. 29.🔺 A current of 40 mA flows through a 300 Ω resistor. What is the voltage across it (in volts)? =
30. 30.🗺️ In “input → process → output”, which part is the decision the program makes? (a) the input (b) the battery (c) the output (d) the process
31. 31.🔍 Which is the odd one out? (a) use a cable with cuts (b) dry your hands first (c) fly a kite near wires (d) touch a fallen wire
32. 32.True or false: a tube light mainly gives out light. (a) False (b) True
33. 33.🧮 A 2.2 V battery is joined to 8 Ω and 3 Ω resistors in series. What current flows (in amperes)? =
34. 34.🧩 Which part changes electrical energy into movement? (a) an LED (b) a fuse (c) a resistor (d) a motor
35. 35.True or false: a tilt switch springs back when let go. (a) True (b) False
36. 36.💡 An LED is joined to a 5 V battery with no resistor; the leg next to the flat edge of its rim goes to the − side. What happens? (a) does not light (b) lights up (c) may burn out
37. 37.🔺 A current of 0.25 A flows when 1.25 V is joined across a resistor. What is its resistance (in ohms)?
38. 38.🌈 Which band is read first on a resistor? (a) the one nearest an end (b) the widest gap (c) the gold band (d) any band
39. 39.💡 Does it save or waste electricity to leave the TV on standby? (a) saves electricity (b) wastes electricity
40. 40.⏱️ loop forever { LED ON; wait 150 ms; LED OFF; wait 100 ms }
    How many times does the LED blink in 3 seconds?

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