Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 907 · 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 home appliance on the 230 V mains takes 0.5 A. What is its power (in watts)?
2. 2.🧾 A 250 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
3. 3.⏱️ A program says “wait 8750 ms”. How many seconds is that? =
4. 4.🔐 Is it a good or a risky habit to ignore update messages? (a) risky habit (b) good habit
5. 5.True or false: a graphite rod is an insulator. (a) True (b) False
6. 6.🔘 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 ON, B is ON and C is ON. Does the bulb glow? (a) No (b) Yes
7. 7.🌈 A resistor has the colour bands white, blue, red. What is its value in kilo-ohms (kΩ)? =
8. 8.🔗 Series or parallel circuit: “bulbs share the voltage”? (a) parallel (b) series
9. 9.✏️ In a circuit diagram, which part is drawn as a circle with V inside? (a) diode (b) battery (c) bulb (d) voltmeter
10. 10.📏 Which unit measures energy used each second? (a) watt (W) (b) volt (V) (c) ampere (A) (d) ohm (Ω)
11. 11.True or false: to unplug idle chargers wastes electricity. (a) False (b) True
12. 12.🔘 A cell, a bulb and switches A, B, C and D are joined one after another in a single loop (series). A is OFF, B is ON, C is OFF and D is ON. Does the bulb glow? (a) No (b) Yes
13. 13.Which job needs a temperature sensor? (a) start a fan when hot (b) stop a robot near walls (c) make a parking alarm (d) open blinds at sunrise
14. 14.Which of these mainly gives out heat? (a) a tube light (b) a loudspeaker (c) a siren (d) a rice cooker
15. 15.🤖 In “if (temp > 30)”, what runs when temp is exactly 30? (a) neither part (b) the else part (c) the if part (d) both parts
16. 16.🔍 A distance sensor sends a sound pulse and hears the echo 1 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?
17. 17.🌐 In an IoT system, which part measures the real world? (a) actuator (b) cloud server (c) sensor (d) phone app
18. 18.True or false: a slide switch flips up or down. (a) True (b) False
19. 19.⏱️ repeat 7 times { buzzer ON; wait 300 ms; buzzer OFF; wait 700 ms }
    How many milliseconds does this take in all?
20. 20.🌈 In the resistor colour code, which number does blue stand for?
21. 21.🧮 Four equal 200 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
22. 22.🔺 A current of 50 mA flows through a 250 Ω resistor. What is the voltage across it (in volts)? =
23. 23.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) stays the same (b) becomes zero (c) gets bigger (d) gets smaller
24. 24.✏️ In a cell symbol, which line is the + terminal? (a) the shorter line (b) both lines (c) the longer line (d) neither line
25. 25.🔺 A current of 2.5 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
26. 26.🔘 Which kind of switch closes when tipped over? (a) a tilt switch (b) a toggle switch (c) a push button (d) a slide switch
27. 27.🔺 A current of 25 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
28. 28.📶 Digital or analog: how loud a sound is? (a) digital (b) analog
29. 29.🔁 repeat 4 times { repeat 5 times { beep } }
    How many beeps are there?
30. 30.🔺 In the V-I-R triangle, how do we find R? (a) R = V ÷ I (b) R = I ÷ V (c) R = V × I (d) R = V + I
31. 31.🗺️ In an input → process → output plan, is “a buzzer beeps” the input, the process or the output? (a) input (b) process (c) output
32. 32.🔺 A current of 0.1 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
33. 33.Which drawing is the symbol for a motor? (a) a circle with a cross (b) a circle with an X in it (c) one tall, one short bar (d) a circle with M inside
34. 34.🔘 A cell, a bulb and switches A and B are joined one after another in a single loop (series). A is ON and B is OFF. Does the bulb glow? (a) Yes (b) No
35. 35.🔋 How many volts does one ordinary torch cell give? (a) 230 V (b) 0.5 V (c) 1.5 V (d) 15 V
36. 36.🔌 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
37. 37.🔺 A 40 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
38. 38.True or false: a steel spoon is an insulator. (a) True (b) False
39. 39.Which of these saves electricity? (a) iron one shirt at a time (b) leave fridge door open (c) use daylight to read (d) leave the TV on standby
40. 40.🔗 Series or parallel circuit: “one bulb out, all go out”? (a) series (b) parallel

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