Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 73 · 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) safe (b) not safe
2. 2.True or false: to close a window in rain, use a rain sensor. (a) False (b) True
3. 3.🔺 A current of 10 mA flows through a 470 Ω resistor. What is the voltage across it (in volts)? =
4. 4.⏱️ repeat 4 times { buzzer ON; wait 800 ms; buzzer OFF; wait 1000 ms }
   How many milliseconds does this take in all?
5. 5.🔁 total = 0
   for i = 1 to 3 { total = total + i }
   What is total at the end?
6. 6.🧮 Resistors of 100 Ω, 10 Ω, 10 Ω and 10 Ω are joined in series. What is the total resistance (in ohms)?
7. 7.💡 5 identical bulbs are joined in series with a battery and a closed switch on the main wire. Bulb 4 is taken out of its holder. How many bulbs glow?
8. 8.True or false: on an LED, the round-side leg is the anode (+). (a) True (b) False
9. 9.🔢 To get a sensor reading onto a phone, which comes first: “the board reads it” or “the sensor measures”? (a) the sensor measures (b) the board reads it
10. 10.⚙️ What is an actuator? (a) a battery (b) a program (c) an output that acts (d) a sensor
11. 11.🔢 To plan an electronics project, which is the LAST step? (a) draw the circuit diagram (b) pick a problem to solve (c) test it and fix it (d) list inputs and outputs
12. 12.⚡ Which tiny particles drift along a metal wire to carry the current? (a) dust particles (b) water drops (c) photons (d) electrons
13. 13.Which of these is a conductor? (a) a plastic ruler (b) a cotton thread (c) a paper strip (d) a steel spoon
14. 14.True or false: “one bulb out, all go out” is true of a parallel circuit. (a) True (b) False
15. 15.💡 4 identical bulbs are joined in parallel across a 6 V battery (ideal wires). How many volts does each bulb get? =
16. 16.🔺 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
17. 17.🤖 In “if (temp > 30)”, what runs when temp is exactly 30? (a) the else part (b) both parts (c) neither part (d) the if part
18. 18.📏 In the water-pipe picture of a circuit, voltage is like … (a) the pipe colour (b) the water tank lid (c) the tap handle (d) the water pressure
19. 19.🤖 if (moisture < 50) { pump ON } else { pump OFF }
    The soil moisture sensor reads 47 %. What happens? (a) pump OFF (b) pump ON
20. 20.⚡ What does a room heater mainly change electricity into? (a) heat (b) movement (c) sound (d) light
21. 21.⏱️ loop forever { LED ON; wait 50 ms; LED OFF; wait 450 ms }
    How many times does the LED blink in 5 seconds?
22. 22.🔁 x = 1
    repeat 4 times { x = x × 2 }
    What is x at the end?
23. 23.🔋 On a cell, does “the shorter symbol line” mean the + end or the − end? (a) − (negative) (b) + (positive)
24. 24.💡 Old festival light strings went fully dark when one bulb failed. How were they joined? (a) in parallel (b) by Wi-Fi (c) not joined (d) in series
25. 25.True or false: to use old filament bulbs saves electricity. (a) True (b) False
26. 26.💡 5 identical bulbs are joined in series with a 7.5 V battery (ideal wires). How many volts does each bulb get? =
27. 27.True or false: a circle with an X in it is the symbol for a bulb. (a) True (b) False
28. 28.💡 Why is house wiring done in parallel? (a) to make bulbs dim (b) to save copper only (c) so all go off together (d) each gets full voltage
29. 29.🔋 6 identical 1.2 V cells are joined in series (+ of one cell to − of the next). What is the total voltage (in volts)? =
30. 30.🔁 What do we call a circuit with a break in it? (a) a full circuit (b) a closed circuit (c) a series circuit (d) an open circuit
31. 31.Which of these is not safe? (a) poke things in a socket (b) take cells out after use (c) dry your hands first (d) stop if a part gets hot
32. 32.True or false: “a soil moisture reading” is the input. (a) False (b) True
33. 33.🤖 if (light < 300) { lamp ON } else { lamp OFF }
    The light sensor reads 232. What happens? (a) lamp ON (b) lamp OFF
34. 34.🔍 Which is the odd one out? (a) a temperature reading (b) a button press (c) a light level reading (d) an LED lights up
35. 35.🔐 Is it a good or a risky habit to change default passwords? (a) risky habit (b) good habit
36. 36.Which of these is an insulator? (a) a wooden stick (b) a steel coin (c) a graphite rod (d) a copper wire
37. 37.🔺 A current of 20 mA flows when 6 V is joined across a resistor. What is its resistance (in ohms)?
38. 38.💡 A red LED uses 2 V and should get 25 mA. It runs from a 5 V supply. What resistor (in ohms) is needed in series?
39. 39.🔘 A cell and a bulb are joined to two side-by-side paths: path 1 has switches A and B one after another, path 2 has switch C. A is OFF, B is ON and C is OFF. Does the bulb glow? (a) Yes (b) No
40. 40.🤖 if (light < 400 AND motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 280 and motion is detected (true). What happens? (a) porch lamp OFF (b) porch lamp ON

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