Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 207 · 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.🔁 count = 4
   while (count < 20) { count = count + 2 }
   How many times does the loop run?
2. 2.Which of these gives us electricity? (a) a washing machine (b) a television (c) an air conditioner (d) a generator
3. 3.🔍 For a microcontroller, is a sensor an input or an output? (a) an input (b) a power source (c) a fuse (d) an output
4. 4.🔢 To run one loop of a plant-watering program, which comes first: “read the soil sensor” or “switch the pump on/off”? (a) read the soil sensor (b) switch the pump on/off
5. 5.💡 2 identical bulbs are in parallel and each one takes 0.2 A. What total current (in amperes) comes from the battery? =
6. 6.Which of these mainly makes sound? (a) an electric iron (b) a mixer grinder (c) a table fan (d) a siren
7. 7.🤖 if (temperature > 31) { show “Hot” } else if (temperature > 18) { show “Warm” } else { show “Cool” }
   The temperature is 21 °C. What is shown? (a) Warm (b) Cool (c) Hot
8. 8.⚡ A home appliance on the 230 V mains takes 5 A. What is its power (in watts)?
9. 9.💡 In a parallel circuit, one bulb breaks. What happens to the others? (a) they explode (b) they all go out (c) they get dimmer (d) they keep glowing
10. 10.🔍 Which is the odd one out? (a) touch a fallen wire (b) throw cells in a fire (c) open a phone charger (d) stop if a part gets hot
11. 11.📏 Which unit measures how much a part resists? (a) volt (V) (b) ohm (Ω) (c) ampere (A) (d) watt (W)
12. 12.🧩 Which component makes a beeping sound? (a) thermistor (b) LDR (c) buzzer (d) diode
13. 13.⚠️ Is it safe to touch a switch when wet? (a) not safe (b) safe
14. 14.🔁 Is the circuit closed or open if all wires are joined? (a) closed (b) open
15. 15.💡 Why does an LED need a resistor in series? (a) to store charge (b) to make it brighter (c) to change its colour (d) to limit the current
16. 16.🔁 x = 3
    repeat 5 times { x = x × 2 }
    What is x at the end?
17. 17.Which of these is not safe? (a) fly kites in open fields (b) use small battery cells (c) take cells out after use (d) poke things in a socket
18. 18.🧮 Resistors of 50 Ω, 68 Ω, 220 Ω and 68 Ω are joined in series. What is the total resistance (in ohms)?
19. 19.⏱️ How many milliseconds is a wait of 1.4 seconds?
20. 20.True or false: to use LED lamps wastes electricity. (a) True (b) False
21. 21.🌈 A gold fourth band on a resistor means the value may be off by … (a) 0 % (b) 5 % (c) 25 % (d) 50 %
22. 22.🔦 A circuit has a new cell, a good bulb and a switch that is OFF. All the wires are firmly joined. A gap in one wire is bridged by a glass marble. Does the bulb glow? (a) No (b) Yes
23. 23.🗺️ In an input → process → output plan, is “a temperature reading” the input, the process or the output? (a) input (b) output (c) process
24. 24.🤖 if (light < 300 AND motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 180 and motion is not detected (false). What happens? (a) porch lamp OFF (b) porch lamp ON
25. 25.🔋 On a cell, does “usually the black wire” mean the + end or the − end? (a) + (positive) (b) − (negative)
26. 26.🔋 Cells joined + to − in a row (series) give … (a) no voltage (b) a smaller voltage (c) the same voltage (d) a bigger voltage
27. 27.🔺 A 2 V supply is joined across a 100 Ω resistor. What current flows (in milliamperes, mA)?
28. 28.Which of these means the circuit is closed? (a) a cell is taken out (b) the loop is complete (c) a wire has come loose (d) the bulb is unscrewed
29. 29.💡 A battery lights 3 identical bulbs joined in series. One more identical bulb is added in series. How do the bulbs glow now? (a) brighter (b) dimmer (c) the same
30. 30.🔺 A current of 0.5 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
31. 31.What does a fuse do? (a) limits the current (b) blows if current is high (c) is a resistance knob (d) lets current go one way
32. 32.🗺️ In an input → process → output plan, is “a buzzer beeps” the input, the process or the output? (a) process (b) input (c) output
33. 33.🔺 A current of 0.1 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
34. 34.🔦 A circuit has a new cell, a good bulb and a switch that is OFF. All the wires are firmly joined. A gap in one wire is bridged by a graphite rod. Does the bulb glow? (a) No (b) Yes
35. 35.🧮 A 47 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)?
36. 36.Which of these is safe? (a) stop if a part gets hot (b) use mains for a project (c) fly a kite near wires (d) use a cable with cuts
37. 37.🔁 What does “count = count + 1” do? (a) sets count to 1 (b) takes 1 away (c) prints 1 (d) adds 1 to count
38. 38.🤖 if (distance < 10) { buzzer beeps } else { buzzer is silent }
    The distance sensor reads 3 cm. What happens? (a) buzzer is silent (b) buzzer beeps
39. 39.⚠️ Is it safe to dry your hands first? (a) not safe (b) safe
40. 40.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a metal paper clip across the gap. Does the bulb glow? (a) Yes (b) No

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