Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 256 · 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 a brass key a conductor or an insulator? (a) an insulator (b) a conductor
2. 2.🔍 Which is the odd one out? (a) decide if soil is dry (b) an LED lights up (c) count button presses (d) compare with a limit
3. 3.Which of these is an output? (a) a motor (b) a keypad (c) a push button (d) a turning knob
4. 4.Which of these means the circuit is closed? (a) a cell is taken out (b) all wires are joined (c) the switch is OFF (d) a wire has come loose
5. 5.🌈 A resistor has the colour bands brown, blue, brown. What is its value (in ohms)?
6. 6.🔋 On a cell, does “the flat end” mean the + end or the − end? (a) + (positive) (b) − (negative)
7. 7.💡 A red LED uses 2 V and should get 25 mA. It runs from a 5 V supply. What resistor (in ohms) is needed in series?
8. 8.⚠️ Is it safe to throw cells in a fire? (a) not safe (b) safe
9. 9.True or false: “own switch for each bulb” is true of a series circuit. (a) False (b) True
10. 10.🔺 A current of 10 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
11. 11.🌈 A resistor has the colour bands yellow, yellow, orange. What is its value in kilo-ohms (kΩ)? =
12. 12.🔁 repeat 6 times { repeat 6 times { beep } }
    How many beeps are there?
13. 13.True or false: to share only needed data is a good habit. (a) False (b) True
14. 14.Which of these is an output? (a) a temperature sensor (b) a push button (c) a sound sensor (d) an LED
15. 15.🔺 A current of 40 mA flows through a 120 Ω resistor. What is the voltage across it (in volts)? =
16. 16.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
17. 17.🔌 Is a motor an input or an output for a microcontroller? (a) input (b) output
18. 18.🔋 On a cell, does “the longer symbol line” mean the + end or the − end? (a) − (negative) (b) + (positive)
19. 19.🔁 repeat 2 times { repeat 3 times { beep } }
    How many beeps are there?
20. 20.Which of these is safe? (a) open a phone charger (b) use mains for a project (c) use small battery cells (d) use a cable with cuts
21. 21.🧾 A 50 W appliance runs for 6 hours. How many units (kWh) of electricity does it use? =
22. 22.🔢 To get a sensor reading onto a phone, which comes first: “the app shows it” or “the sensor measures”? (a) the app shows it (b) the sensor measures
23. 23.📏 How many watts (W) is 0.5 kW?
24. 24.⚠️ Is it safe to fly kites in open fields? (a) not safe (b) safe
25. 25.Which job needs a servo motor? (a) beep an alarm (b) open a gate to 90° (c) spin a robot’s wheels (d) show a status light
26. 26.True or false: on a cell, “the flat end” means the − (negative) end. (a) True (b) False
27. 27.True or false: to fly a kite near wires is safe. (a) False (b) True
28. 28.Which of these is an insulator? (a) a copper wire (b) an iron nail (c) a graphite rod (d) a wooden stick
29. 29.⚡ Which formula gives electric power? (a) P = V + I (b) P = V ÷ I (c) P = V × I (d) P = I ÷ V
30. 30.True or false: power is measured in amperes (A). (a) True (b) False
31. 31.🔍 Which is the odd one out? (a) a woollen thread (b) a steel coin (c) a rubber eraser (d) a cotton thread
32. 32.🧩 Which part changes electrical energy into movement? (a) a fuse (b) an LED (c) a motor (d) a resistor
33. 33.🌈 A resistor has the colour bands violet, brown, red. What is its value (in ohms)?
34. 34.📏 In the water-pipe picture of a circuit, voltage is like … (a) the water tank lid (b) the tap handle (c) the pipe colour (d) the water pressure
35. 35.🔍 Which sensor would you use to water a dry plant? (a) a gas sensor (b) a soil moisture sensor (c) a rain sensor (d) a motion sensor
36. 36.⚡ A home appliance on the 230 V mains takes 2 A. What is its power (in watts)?
37. 37.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a brass key across the gap. Does the bulb glow? (a) No (b) Yes
38. 38.🗺️ In an input → process → output plan, is “decide if soil is dry” the input, the process or the output? (a) input (b) process (c) output
39. 39.💡 A blue LED uses 3 V and should get 10 mA. It runs from a 6 V supply. What resistor (in ohms) is needed in series?
40. 40.True or false: a reed switch springs back when let go. (a) True (b) False

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