Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 139 · 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.💡 Does it save or waste electricity to unplug idle chargers? (a) wastes electricity (b) saves electricity
2. 2.📏 Voltmeter or ammeter: which one is joined across a part? (a) ammeter (b) voltmeter
3. 3.🌈 Which band is read first on a resistor? (a) any band (b) the widest gap (c) the gold band (d) the one nearest an end
4. 4.🧮 Two equal 40 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
5. 5.True or false: a water heater mainly gives out light. (a) True (b) False
6. 6.💡 2 identical bulbs are joined in series with a 3 V battery (ideal wires). How many volts does each bulb get? =
7. 7.True or false: power is measured in watts (W). (a) False (b) True
8. 8.⚠️ Is it safe to touch a fallen wire? (a) safe (b) not safe
9. 9.🧩 Which part changes electrical energy into sound? (a) a capacitor (b) a resistor (c) a buzzer (d) a diode
10. 10.🧮 A 1 V battery is joined to 2 Ω and 8 Ω resistors in series. What current flows (in amperes)? =
11. 11.💡 A red LED (it uses 2 V) is joined with a 150 Ω resistor to a 4.25 V supply. What current flows (in mA)?
12. 12.True or false: to keep an incubator warm, use a soil moisture sensor. (a) True (b) False
13. 13.🔍 Which is the odd one out? (a) leave the TV on standby (b) leave fridge door open (c) unplug idle chargers (d) run fans in empty rooms
14. 14.True or false: a wind-up toy has no microcontroller inside. (a) True (b) False
15. 15.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a rubber band across the gap. Does the bulb glow? (a) No (b) Yes
16. 16.🧩 Which part changes electrical energy into movement? (a) a motor (b) a fuse (c) an LED (d) a resistor
17. 17.🔍 Which is the odd one out? (a) the pump turns on (b) count button presses (c) the fan starts (d) a buzzer beeps
18. 18.🔺 A current of 50 mA flows when 20 V is joined across a resistor. What is its resistance (in ohms)?
19. 19.Which drawing is the symbol for a battery? (a) triangle, bar and arrows (b) two or more cell symbols (c) triangle against a bar (d) two equal parallel lines
20. 20.⚠️ Is it safe to take cells out after use? (a) not safe (b) safe
21. 21.Which of these means the circuit is closed? (a) the loop is complete (b) the switch is OFF (c) a cell is taken out (d) the bulb is unscrewed
22. 22.True or false: to touch a switch when wet is safe. (a) True (b) False
23. 23.Which job needs a servo motor? (a) show the temperature (b) turn to an exact angle (c) show a status light (d) beep an alarm
24. 24.True or false: a washing machine usually has a microcontroller inside. (a) True (b) False
25. 25.🧮 Resistors of 20 Ω and 20 Ω are joined in series. What is the total resistance (in ohms)?
26. 26.True or false: on a cell, “the longer symbol line” means the + (positive) end. (a) True (b) False
27. 27.True or false: to build with an adult near is safe. (a) False (b) True
28. 28.💡 A battery lights 2 identical bulbs joined in series. One more identical bulb is added in series. How do the bulbs glow now? (a) brighter (b) the same (c) dimmer
29. 29.📏 In the water-pipe picture of a circuit, voltage is like … (a) the pipe colour (b) the tap handle (c) the water tank lid (d) the water pressure
30. 30.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) becomes zero (b) stays the same (c) gets bigger (d) gets smaller
31. 31.What does a tilt switch do? (a) flips up or down (b) stays where you flip it (c) closes when tipped over (d) works only while pressed
32. 32.🤖 Which is a safe power source for a beginner microcontroller board? (a) bare mains wires (b) a 230 V cable (c) USB or a 9 V battery (d) a wall socket directly
33. 33.⏱️ How many milliseconds is a wait of 1.4 seconds?
34. 34.Which of these is measured in volts (V)? (a) how much a part resists (b) energy used each second (c) the push of a cell (d) the flow of charge
35. 35.💡 In a parallel circuit, one bulb breaks. What happens to the others? (a) they keep glowing (b) they get dimmer (c) they all go out (d) they explode
36. 36.Which of these has no microcontroller inside? (a) a digital thermometer (b) a spinning top (c) a washing machine (d) a digital alarm clock
37. 37.Which of these is a conductor? (a) a copper wire (b) a cotton thread (c) a ceramic cup (d) a plastic straw
38. 38.🔋 On a cell, does “usually the red wire” mean the + end or the − end? (a) + (positive) (b) − (negative)
39. 39.🔁 What does a variable do in a program? (a) joins two wires (b) blinks an LED (c) measures light (d) stores a value
40. 40.Which of these is not safe? (a) keep drinks far away (b) stay away from pylons (c) fly kites in open fields (d) touch a switch when wet

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