Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 984 · 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.⚡ What does a loudspeaker mainly change electricity into? (a) heat (b) sound (c) movement (d) light
2. 2.⏱️ loop forever { LED ON; wait 300 ms; LED OFF; wait 350 ms }
   How many milliseconds does one blink (ON + OFF) take?
3. 3.🔗 Series or parallel circuit: “each gets the full volts”? (a) parallel (b) series
4. 4.True or false: a circle with A inside is the symbol for a cell. (a) True (b) False
5. 5.🔍 Which is the odd one out? (a) an alert on the phone (b) decide if soil is dry (c) the pump turns on (d) an LED lights up
6. 6.🔌 Why are electric wires covered in plastic? (a) plastic makes current (b) plastic is a conductor (c) plastic is an insulator (d) to make them heavy
7. 7.🧮 Two equal 10 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
8. 8.💡 An LED (with its resistor) is on pin 7. All pins start LOW. The program runs once:
   set pin 7 HIGH
   set pin 7 LOW
   set pin 7 HIGH
   set pin 8 LOW
   Is the LED ON or OFF at the end? (a) ON (b) OFF
9. 9.🌈 A gold fourth band on a resistor means the value may be off by … (a) 5 % (b) 25 % (c) 0 % (d) 50 %
10. 10.⏱️ What does “wait 500 ms” do? (a) blinks 500 times (b) waits 500 seconds (c) pauses for half a second (d) turns the LED off
11. 11.✏️ In a circuit diagram, which part is drawn as triangle, bar and arrows? (a) switch (b) voltmeter (c) cell (d) LED
12. 12.⚡ A 3 W device works on 12 V. What current does it take (in amperes)? =
13. 13.🧩 Which component stores a little charge? (a) transistor (b) LDR (c) buzzer (d) capacitor
14. 14.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark an 810 Ω resistor? (a) grey-brown-black (b) grey-brown-red (c) grey-brown-brown (d) brown-grey-brown
15. 15.🔋 Cells joined + to − in a row (series) give … (a) the same voltage (b) no voltage (c) a bigger voltage (d) a smaller voltage
16. 16.Which of these is the input? (a) a motion sensor signal (b) check if temp > 30 (c) compare with a limit (d) the pump turns on
17. 17.🗺️ In an input → process → output plan, is “a buzzer beeps” the input, the process or the output? (a) output (b) process (c) input
18. 18.🤖 “if (A AND B)” is true when … (a) only A is true (b) only B is true (c) both A and B are true (d) both are false
19. 19.🔍 An object is 170 cm from a distance sensor. Sound travels about 34 cm every millisecond. After how many milliseconds does the echo come back?
20. 20.💡 An LED (with its resistor) is on pin 8. All pins start LOW. The program runs once:
    set pin 8 HIGH
    set pin 7 LOW
    Is the LED ON or OFF at the end? (a) ON (b) OFF
21. 21.⚠️ Is it safe to stop if a part gets hot? (a) safe (b) not safe
22. 22.💡 An LED is joined to a 3 V battery through a 330 Ω resistor; its long leg goes to the − side and its short leg to the + side. What happens? (a) may burn out (b) does not light (c) lights up
23. 23.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets bigger (b) stays the same (c) becomes zero (d) gets smaller
24. 24.🔋 3 identical 1.5 V cells are joined in series (+ of one cell to − of the next). What is the total voltage (in volts)? =
25. 25.🔘 Two switches are in series. When does the bulb glow? (a) when both are ON (b) never (c) when both are OFF (d) when either is ON
26. 26.💡 3 identical bulbs are joined in series with a 6 V battery (ideal wires). How many volts does each bulb get? =
27. 27.🔺 A current of 0.1 A flows when 1.2 V is joined across a resistor. What is its resistance (in ohms)?
28. 28.True or false: “one out, the rest glow” is true of a series circuit. (a) True (b) False
29. 29.🔋 What is a battery? (a) two or more cells joined (b) a kind of bulb (c) one single wire (d) a switch with a lid
30. 30.⚡ Which formula gives electric power? (a) P = V × I (b) P = V + I (c) P = I ÷ V (d) P = V ÷ I
31. 31.💡 Why is house wiring done in parallel? (a) to save copper only (b) to make bulbs dim (c) so all go off together (d) each gets full voltage
32. 32.🔺 A 3.75 V supply is joined across a 150 Ω resistor. What current flows (in milliamperes, mA)?
33. 33.🧾 A 2000 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
34. 34.Which of these is a risky habit? (a) change default passwords (b) reuse one password (c) turn off unused gadgets (d) log out of shared phones
35. 35.True or false: on a cell, “the longer symbol line” means the + (positive) end. (a) True (b) False
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.🤖 In “if (temp > 30)”, what runs when temp is exactly 30? (a) both parts (b) the if part (c) the else part (d) neither part
38. 38.🔺 In the V-I-R triangle, how do we find V? (a) V = R ÷ I (b) V = I ÷ R (c) V = I × R (d) V = I + R
39. 39.Which of these is measured in volts (V)? (a) resistance (b) how much a part resists (c) voltage (d) the flow of charge
40. 40.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)

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