Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 927 · 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.🧩 Which component boosts a small signal? (a) transistor (b) motor (c) potentiometer (d) diode
2. 2.Which drawing is the symbol for a cell? (a) triangle, bar and arrows (b) a long and a short line (c) a circle with V inside (d) triangle against a bar
3. 3.⏱️ A program says “wait 3500 ms”. How many seconds is that? =
4. 4.🔋 6 identical 1.5 V cells are joined in series (+ of one cell to − of the next). What is the total voltage (in volts)? =
5. 5.🌈 A resistor has the colour bands orange, green, yellow. What is its value in kilo-ohms (kΩ)? =
6. 6.⚙️ What is an actuator? (a) a program (b) a battery (c) an output that acts (d) a sensor
7. 7.🔺 A current of 20 mA flows when 2 V is joined across a resistor. What is its resistance (in ohms)?
8. 8.⏱️ loop forever { LED ON; wait 100 ms; LED OFF; wait 900 ms }
   How many times does the LED blink in 5 seconds?
9. 9.🌐 A soil sensor sends a reading to an app every 5 minutes. How many readings arrive in 1 hour?
10. 10.Which of these uses electricity? (a) a wind turbine (b) a television (c) a cell (d) a power station
11. 11.🔌 Why are electric wires covered in plastic? (a) plastic makes current (b) plastic is an insulator (c) plastic is a conductor (d) to make them heavy
12. 12.🔘 A cell, a bulb and switches A and B are joined one after another in a single loop (series). A is OFF and B is OFF. Does the bulb glow? (a) No (b) Yes
13. 13.True or false: a microcontroller runs one small program. (a) False (b) True
14. 14.🔘 Which kind of switch works only while pressed? (a) a toggle switch (b) a reed switch (c) a push button (d) a slide switch
15. 15.🤖 if (temperature > 37) { show “Hot” } else if (temperature > 22) { show “Warm” } else { show “Cool” }
    The temperature is 30 °C. What is shown? (a) Hot (b) Cool (c) Warm
16. 16.True or false: power is measured in amperes (A). (a) True (b) False
17. 17.⚡ A home appliance on the 230 V mains takes 1 A. What is its power (in watts)?
18. 18.🧾 Which lamp gives the same light for the least power? (a) an LED lamp (b) a candle (c) a filament bulb (d) an oil lamp
19. 19.🔺 In the V-I-R triangle, how do we find I? (a) I = V ÷ R (b) I = V × R (c) I = R ÷ V (d) I = V + R
20. 20.⏱️ loop forever { LED ON; wait 400 ms; LED OFF; wait 500 ms }
    How many milliseconds does one blink (ON + OFF) take?
21. 21.True or false: to use LED lamps wastes electricity. (a) True (b) False
22. 22.🧩 Which component makes things spin? (a) motor (b) potentiometer (c) buzzer (d) capacitor
23. 23.🌈 A resistor has the colour bands yellow, brown, black. What is its value (in ohms)?
24. 24.Which of these mainly makes movement? (a) a mixer grinder (b) an electric iron (c) a siren (d) an LED lamp
25. 25.🔘 What does a switch do in a circuit? (a) stores current (b) changes the voltage (c) opens or closes the loop (d) makes electricity
26. 26.True or false: “a single current path” is true of a series circuit. (a) False (b) True
27. 27.🔺 A current of 20 mA flows through a 120 Ω resistor. What is the voltage across it (in volts)? =
28. 28.⏱️ loop forever { LED ON; wait 150 ms; LED OFF; wait 50 ms }
    How many times does the LED blink in 2 seconds?
29. 29.Which of these is measured in amperes (A)? (a) current (b) power (c) how much a part resists (d) energy used each second
30. 30.🔍 A distance sensor sends a sound pulse and hears the echo 5 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?
31. 31.🔗 Series or parallel circuit: “a break stops every bulb”? (a) parallel (b) series
32. 32.True or false: an exhaust fan mainly makes sound. (a) True (b) False
33. 33.⏱️ What does “wait 500 ms” do? (a) pauses for half a second (b) waits 500 seconds (c) turns the LED off (d) blinks 500 times
34. 34.🌈 In the resistor colour code, which number does green stand for?
35. 35.True or false: on a cell, “usually the red wire” means the − (negative) end. (a) True (b) False
36. 36.💡 Does it save or waste electricity to close the fridge quickly? (a) wastes electricity (b) saves electricity
37. 37.🔍 Which is the odd one out? (a) build with an adult near (b) open a phone charger (c) climb an electric pole (d) poke things in a socket
38. 38.🧩 Which component blows if current is high? (a) LED (b) buzzer (c) LDR (d) fuse
39. 39.⚡ A device works on 12 V and takes 0.1 A. What is its power (in watts)? =
40. 40.Which job is done by the power LED? (a) brings power and code (b) shows the board is on (c) restarts the program (d) runs the program

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