Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 809 · 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.🌈 In the resistor colour code, which number does orange stand for?
2. 2.⚡ A 1.8 W device works on 9 V. What current does it take (in amperes)? =
3. 3.✏️ In a circuit diagram, which part is drawn as two equal parallel lines? (a) bulb (b) resistor (c) motor (d) capacitor
4. 4.🤖 if (light < 200 AND motion) { porch lamp ON } else { porch lamp OFF }
   The light reading is 100 and motion is not detected (false). What happens? (a) porch lamp ON (b) porch lamp OFF
5. 5.True or false: “many paths for current” is true of a parallel circuit. (a) True (b) False
6. 6.🔍 A distance sensor sends a sound pulse and hears the echo 16 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?
7. 7.🔌 A gap of dry air between two wires acts as … (a) a cell (b) an insulator (c) a conductor (d) a switch that is ON
8. 8.🔍 Which is the odd one out? (a) use LED lamps (b) use daylight to read (c) leave fridge door open (d) switch off empty rooms
9. 9.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) none (b) it does not matter (c) both of them (d) only one
10. 10.Which of these is a good habit? (a) share camera links (b) tap unknown app links (c) share the Wi-Fi key (d) share only needed data
11. 11.💡 A battery lights 5 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
12. 12.💡 Why does an LED need a resistor in series? (a) to change its colour (b) to store charge (c) to limit the current (d) to make it brighter
13. 13.🔺 In the V-I-R triangle, how do we find I? (a) I = V × R (b) I = R ÷ V (c) I = V + R (d) I = V ÷ R
14. 14.🗺️ In an input → process → output plan, is “check if temp > 30” the input, the process or the output? (a) input (b) output (c) process
15. 15.Which of these means the circuit is closed? (a) a cell is taken out (b) a wire has come loose (c) the loop is complete (d) a wire is cut
16. 16.🧮 Adding another resistor in series makes the total resistance … (a) zero (b) smaller (c) stay the same (d) bigger
17. 17.True or false: to stop a robot near walls, use a temperature sensor. (a) False (b) True
18. 18.🔺 A current of 1 A flows when 10 V is joined across a resistor. What is its resistance (in ohms)?
19. 19.✏️ In a circuit diagram, which part is drawn as a straight line? (a) wire (b) bulb (c) cell (d) diode
20. 20.💡 A red LED uses 2 V and should get 10 mA. It runs from a 12 V supply. What resistor (in ohms) is needed in series?
21. 21.🌈 A resistor has the colour bands red, white, yellow. What is its value in kilo-ohms (kΩ)? =
22. 22.Which of these uses electricity? (a) a washing machine (b) a bicycle dynamo (c) a generator (d) a solar panel
23. 23.🔋 How many 3 V cells must be joined in series to give 6 V?
24. 24.Which of these is true of a series circuit? (a) one out, the rest glow (b) used in house wiring (c) a break stops every bulb (d) own switch for each bulb
25. 25.True or false: “count button presses” is the output. (a) True (b) False
26. 26.🔌 Which metal is used for most electric wires at home? (a) copper (b) rubber (c) glass (d) plastic
27. 27.🔺 A current of 0.2 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
28. 28.What does a toggle switch do? (a) works only while pressed (b) stays where you flip it (c) springs back when let go (d) closes when tipped over
29. 29.⚠️ Is it safe to climb an electric pole? (a) safe (b) not safe
30. 30.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
31. 31.📶 Digital or analog: a door: open or shut? (a) analog (b) digital
32. 32.⏱️ loop forever { LED ON; wait 1000 ms; LED OFF; wait 1000 ms }
    How many times does the LED blink in 12 seconds?
33. 33.💡 3 identical bulbs are in parallel and each bulb has its own switch on its path. 1 of the switches is OFF and the rest are ON. How many bulbs glow?
34. 34.🔍 Which is the odd one out? (a) a light sensor (b) a servo motor (c) a push button (d) a sound sensor
35. 35.🤖 Microcontroller or laptop: which one runs many apps at once? (a) laptop (b) microcontroller
36. 36.🔘 Switch A is on the main wire next to the cell and the bulb; then the wire splits into two side-by-side paths, one with switch B and one with switch C. A is OFF, B is ON and C is ON. Does the bulb glow? (a) Yes (b) No
37. 37.True or false: a motor senses how hot it is. (a) True (b) False
38. 38.Which of these is not safe? (a) fly kites in open fields (b) use small battery cells (c) stay away from pylons (d) fly a kite near wires
39. 39.⏱️ How many milliseconds are in 1 second? (a) 100 (b) 1000 (c) 10 (d) 60
40. 40.⚡ A device works on 24 V and takes 0.5 A. What is its power (in watts)? =

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