Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 10 · 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 25 mA flows through a 250 Ω resistor. What is the voltage across it (in volts)? =
2. 2.✏️ In a circuit diagram, which part is drawn as a circle with a cross? (a) diode (b) switch (c) bulb (d) ammeter
3. 3.💡 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) dimmer (c) the same
4. 4.📶 Digital or analog: a knob turned part way? (a) analog (b) digital
5. 5.📏 Voltmeter or ammeter: which one is joined across a part? (a) ammeter (b) voltmeter
6. 6.🧩 Which component senses how bright it is? (a) transistor (b) fuse (c) LED (d) LDR
7. 7.True or false: on an LED, the leg by the flat edge is the cathode (−). (a) True (b) False
8. 8.🌐 A soil sensor sends a reading to an app every 5 minutes. How many readings arrive in 5 hours?
9. 9.🔺 A current of 0.2 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
10. 10.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. Does the bulb glow? (a) Yes (b) No
11. 11.💡 A battery lights 2 identical bulbs joined in parallel. One more identical bulb is added in parallel. How do the bulbs glow now? (a) the same (b) brighter (c) dimmer
12. 12.🔐 Is it a good or a risky habit to set up with a parent? (a) good habit (b) risky habit
13. 13.🔍 Which is the odd one out? (a) a steel coin (b) a plastic ruler (c) a copper wire (d) a graphite rod
14. 14.⚠️ Is it safe to touch a fallen wire? (a) not safe (b) safe
15. 15.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a wooden stick across the gap. Does the bulb glow? (a) No (b) Yes
16. 16.🔍 Which is the odd one out? (a) a turning knob (b) a buzzer (c) a speaker (d) a motor
17. 17.🧮 Resistors of 20 Ω, 150 Ω and 47 Ω are joined in series. What is the total resistance (in ohms)?
18. 18.🔺 A current of 2 A flows when 24 V is joined across a resistor. What is its resistance (in ohms)?
19. 19.📏 How many watts (W) is 1.6 kW?
20. 20.Which of these is a conductor? (a) a safety pin (b) a glass marble (c) a plastic ruler (d) a wooden stick
21. 21.🔢 To plan an electronics project, which is the FIRST step? (a) test it and fix it (b) draw the circuit diagram (c) list inputs and outputs (d) pick a problem to solve
22. 22.🔍 Which sensor would you use to open blinds at sunrise? (a) a soil moisture sensor (b) a temperature sensor (c) a gas sensor (d) a light sensor
23. 23.Which drawing is the symbol for a voltmeter? (a) one tall, one short bar (b) a circle with V inside (c) triangle against a bar (d) a straight line
24. 24.True or false: on an LED, the round-side leg is the cathode (−). (a) False (b) True
25. 25.Which of these is measured in ohms (Ω)? (a) the push of a cell (b) power (c) resistance (d) energy used each second
26. 26.True or false: a night lamp mainly makes sound. (a) True (b) False
27. 27.⚠️ Which power source should children use for electronics projects? (a) a mains extension board (b) a wall socket (c) an inverter socket (d) a small battery pack
28. 28.🔍 A distance sensor sends a sound pulse and hears the echo 5 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?
29. 29.🔍 Which is the odd one out? (a) a motion sensor signal (b) a button press (c) check if temp > 30 (d) a light level reading
30. 30.🌈 A resistor has the colour bands green, violet, yellow. What is its value in kilo-ohms (kΩ)? =
31. 31.🌈 A resistor has the colour bands red, violet, orange. What is its value in kilo-ohms (kΩ)? =
32. 32.📏 In the water-pipe picture of a circuit, voltage is like … (a) the tap handle (b) the water tank lid (c) the water pressure (d) the pipe colour
33. 33.What does a transistor do? (a) senses how bright it is (b) makes a beeping sound (c) boosts a small signal (d) smooths a wobbly supply
34. 34.Which of these is true of a parallel circuit? (a) bulbs share the voltage (b) each gets the full volts (c) one bulb out, all go out (d) a break stops every bulb
35. 35.🔘 Two switches are in series. When does the bulb glow? (a) never (b) when either is ON (c) when both are ON (d) when both are OFF
36. 36.⚙️ Which actuator would you use to move water to plants? (a) a pump (b) a servo motor (c) a buzzer (d) an LED
37. 37.⚡ Power tells us … (a) the length of a wire (b) energy used each second (c) the size of a cell (d) the colour of light
38. 38.True or false: on an LED, the leg by the flat edge is the anode (+). (a) False (b) True
39. 39.True or false: on a cell, “the end with a bump” means the + (positive) end. (a) True (b) False
40. 40.🧮 Adding another resistor in series makes the total resistance … (a) smaller (b) bigger (c) zero (d) stay the same

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