Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 238 · 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 it safe to climb an electric pole? (a) not safe (b) safe
2. 2.Which job needs a pump? (a) show a status light (b) show the temperature (c) move water to plants (d) turn to an exact angle
3. 3.True or false: on an LED, the longer leg is the anode (+). (a) False (b) True
4. 4.💡 An LED (with its resistor) is on pin 7. All pins start LOW. The program runs once:
   set pin 7 HIGH
   set pin 7 HIGH
   set pin 8 HIGH
   set pin 7 LOW
   Is the LED ON or OFF at the end? (a) ON (b) OFF
5. 5.⏱️ repeat 2 times { buzzer ON; wait 100 ms; buzzer OFF; wait 900 ms }
   How many milliseconds does this take in all?
6. 6.🔺 An 11.75 V supply is joined across a 470 Ω resistor. What current flows (in milliamperes, mA)?
7. 7.🧮 Resistors of 330 Ω, 50 Ω, 220 Ω and 50 Ω are joined in series. What is the total resistance (in ohms)?
8. 8.True or false: to warn of a gas leak, use a sound sensor. (a) False (b) True
9. 9.✏️ In a cell symbol, which line is the + terminal? (a) neither line (b) the longer line (c) the shorter line (d) both lines
10. 10.🔺 A current of 25 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
11. 11.Which of these is not safe? (a) fly kites in open fields (b) keep drinks far away (c) use a cable with cuts (d) use small battery cells
12. 12.🧮 A 5 V battery is joined to 5 Ω and 5 Ω resistors in series. What current flows (in amperes)? =
13. 13.✏️ In a circuit diagram, which part is drawn as a line lifted at a gap? (a) wire (b) switch (c) ammeter (d) junction
14. 14.🔁 What does a variable do in a program? (a) joins two wires (b) measures light (c) stores a value (d) blinks an LED
15. 15.What does a push button do? (a) springs back when let go (b) closes when tipped over (c) flips up or down (d) closes near a magnet
16. 16.⚠️ Which power source should children use for electronics projects? (a) a wall socket (b) a mains extension board (c) a small battery pack (d) an inverter socket
17. 17.Which of these is the process? (a) a motion sensor signal (b) the pump turns on (c) a light level reading (d) check if temp > 30
18. 18.🔁 count = 7
    repeat 9 times { count = count + 6 }
    What is count at the end?
19. 19.⏱️ How many milliseconds is a wait of 0.9 seconds?
20. 20.🔘 Which kind of switch flips up or down? (a) a push button (b) a reed switch (c) a toggle switch (d) a slide switch
21. 21.Which of these saves electricity? (a) unplug idle chargers (b) run fans in empty rooms (c) iron one shirt at a time (d) leave the TV on standby
22. 22.True or false: to leave fridge door open wastes electricity. (a) False (b) True
23. 23.🤖 “if (A AND B)” is true when … (a) both are false (b) both A and B are true (c) only A is true (d) only B is true
24. 24.✏️ In a circuit diagram, which part is drawn as a circle with A inside? (a) voltmeter (b) ammeter (c) capacitor (d) bulb
25. 25.🔘 A cell and a bulb are joined to 3 side-by-side paths with one switch on each path — A, B and C (parallel). A is OFF, B is OFF and C is OFF. Does the bulb glow? (a) No (b) Yes
26. 26.🌐 A soil sensor sends a reading to an app every 10 minutes. How many readings arrive in 1 hour?
27. 27.🔐 A smart speaker is always listening for its wake word. What is a sensible habit? (a) tell it your passwords (b) let strangers use it (c) mute it when not in use (d) put it in the bathroom
28. 28.💡 A battery lights 3 identical bulbs joined in series. One more identical bulb is added in series. How do the bulbs glow now? (a) dimmer (b) brighter (c) the same
29. 29.🔺 A current of 3 A flows when 36 V is joined across a resistor. What is its resistance (in ohms)?
30. 30.🧩 Which component senses how bright it is? (a) diode (b) LED (c) motor (d) LDR
31. 31.True or false: a straight line is the symbol for an LED. (a) True (b) False
32. 32.🔋 A 3 V battery and one 1.5 V cell are joined in series, all facing the same way. What is the total voltage (in volts)? =
33. 33.🔦 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
34. 34.🔍 Which is the odd one out? (a) reuse one password (b) set up with a parent (c) share camera links (d) tap unknown app links
35. 35.🧮 Two equal 50 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
36. 36.💡 Does it save or waste electricity to use LED lamps? (a) wastes electricity (b) saves electricity
37. 37.🔺 A 30 V supply is joined across a 12 Ω resistor. What current flows (in amperes)? =
38. 38.💡 An LED (with its resistor) is on pin 7. All pins start LOW. The program runs once:
    set pin 8 LOW
    set pin 8 HIGH
    set pin 8 LOW
    set pin 7 LOW
    set pin 8 HIGH
    Is the LED ON or OFF at the end? (a) ON (b) OFF
39. 39.🔺 A current of 2.5 A flows when 20 V is joined across a resistor. What is its resistance (in ohms)?
40. 40.🔺 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

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