Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 673 · 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 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
2. 2.🔺 A current of 2.5 A flows when 5 V is joined across a resistor. What is its resistance (in ohms)?
3. 3.💡 Why does an LED need a resistor in series? (a) to make it brighter (b) to change its colour (c) to store charge (d) to limit the current
4. 4.💡 What happens if an LED is put in backwards? (a) it lights brighter (b) it does not light (c) it changes colour (d) it makes a sound
5. 5.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a brass key across the gap. Does the bulb glow? (a) No (b) Yes
6. 6.🧭 Which part of a microcontroller board restarts the program? (a) the voltage regulator (b) the pins (c) the reset button (d) the main chip
7. 7.🔁 repeat 4 times { repeat 4 times { beep } }
   How many beeps are there?
8. 8.⏱️ loop forever { LED ON; wait 600 ms; LED OFF; wait 50 ms }
   How many milliseconds does one blink (ON + OFF) take?
9. 9.🧭 Which part of a microcontroller board brings power and code? (a) the USB port (b) the main chip (c) the pins (d) the power LED
10. 10.🌈 A resistor has the colour bands green, brown, red. What is its value in kilo-ohms (kΩ)? =
11. 11.💡 A battery lights 3 identical bulbs joined in series. One more identical bulb is added in series. How do the bulbs glow now? (a) the same (b) dimmer (c) brighter
12. 12.📶 Digital or analog: the room temperature? (a) analog (b) digital
13. 13.Which of these is an input? (a) an LED (b) a water pump (c) a motor (d) a push button
14. 14.✏️ In a circuit diagram, which part is drawn as a circle with a cross? (a) diode (b) switch (c) bulb (d) ammeter
15. 15.True or false: the ammeter measures current. (a) False (b) True
16. 16.Which job is done by the reset button? (a) brings power and code (b) restarts the program (c) runs the program (d) connect sensors and LEDs
17. 17.True or false: to use LED lamps saves electricity. (a) False (b) True
18. 18.🧮 Three equal 30 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
19. 19.🌐 In an IoT system, which part measures the real world? (a) sensor (b) phone app (c) Wi-Fi (d) microcontroller
20. 20.⚡ What does a traffic signal mainly change electricity into? (a) light (b) heat (c) movement (d) sound
21. 21.🧩 A capacitor in a circuit can … (a) make light (b) spin a wheel (c) measure heat (d) store charge briefly
22. 22.Which of these is a risky habit? (a) change default passwords (b) log out of shared phones (c) set up with a parent (d) reuse one password
23. 23.🔍 A distance sensor sends a sound pulse and hears the echo 3 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?
24. 24.🔘 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 OFF and C is OFF. Does the bulb glow? (a) Yes (b) No
25. 25.🧩 Which component has coloured bands? (a) thermistor (b) resistor (c) LED (d) motor
26. 26.True or false: the voltmeter measures current. (a) True (b) False
27. 27.🔘 A cell and a bulb are joined to 2 side-by-side paths with one switch on each path — A and B (parallel). A is OFF and B is OFF. Does the bulb glow? (a) No (b) Yes
28. 28.⚡ A home appliance on the 230 V mains takes 4 A. What is its power (in watts)?
29. 29.🔌 Is a paper strip a conductor or an insulator? (a) an insulator (b) a conductor
30. 30.🔘 When a switch is ON, the circuit is … (a) open (b) cut (c) broken (d) closed
31. 31.Which of these mainly gives out light? (a) a toaster (b) an LED lamp (c) a school bell (d) a doorbell
32. 32.⏱️ loop forever { LED ON; wait 150 ms; LED OFF; wait 100 ms }
    How many times does the LED blink in 6 seconds?
33. 33.🌐 A weather station sends one reading every 60 seconds. How many readings does it send in 1 minute?
34. 34.🔌 Which part of a screwdriver should an electrician hold? (a) the bare end (b) the metal tip (c) the plastic handle (d) the steel shaft
35. 35.⏱️ How many milliseconds are in 1 second? (a) 10 (b) 60 (c) 100 (d) 1000
36. 36.💡 3 identical bulbs are joined in series with a 7.5 V battery (ideal wires). How many volts does each bulb get? =
37. 37.🧮 A 0.8 V battery is joined to 5 Ω and 3 Ω resistors in series. What current flows (in amperes)? =
38. 38.True or false: if the switch is OFF, the circuit is closed and current flows. (a) True (b) False
39. 39.🔁 What do we call a circuit with a break in it? (a) a closed circuit (b) a full circuit (c) an open circuit (d) a series circuit
40. 40.Which of these is true of a series circuit? (a) one out, the rest glow (b) own switch for each bulb (c) each gets the full volts (d) one bulb out, all go out

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