Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 565 · 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.True or false: a metal paper clip is a conductor. (a) False (b) True
2. 2.⏱️ loop forever { LED ON; wait 250 ms; LED OFF; wait 850 ms }
   How many milliseconds does one blink (ON + OFF) take?
3. 3.True or false: “an alert on the phone” is the output. (a) True (b) False
4. 4.⚡ A device works on 3 V and takes 2 A. What is its power (in watts)? =
5. 5.⏱️ A program says “wait 1000 ms”. How many seconds is that? =
6. 6.⚡ A device works on 9 V and takes 0.5 A. What is its power (in watts)? =
7. 7.True or false: a circle with M inside is the symbol for a junction. (a) True (b) False
8. 8.🌈 A resistor has the colour bands yellow, violet, red. What is its value (in ohms)?
9. 9.True or false: “a button: pressed or not” is a digital signal. (a) False (b) True
10. 10.🤖 if (sound > 60) { red LED ON } else { green LED ON }
    The sound sensor reads 40. What happens? (a) red LED ON (b) green LED ON
11. 11.🔺 A current of 0.1 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
12. 12.🔁 Is the circuit closed or open if the bulb is unscrewed? (a) closed (b) open
13. 13.⚡ What does a tube light mainly change electricity into? (a) movement (b) heat (c) light (d) sound
14. 14.🔋 6 identical 1.5 V cells are joined in series, but one of them is put in the wrong way round. What is the total voltage now (in volts)? =
15. 15.🔺 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
16. 16.Which of these is safe? (a) poke things in a socket (b) use mains for a project (c) fly kites in open fields (d) climb an electric pole
17. 17.🔍 Which is the odd one out? (a) count button presses (b) a light level reading (c) a button press (d) a soil moisture reading
18. 18.⚙️ Which actuator would you use to open a gate to 90°? (a) a servo motor (b) a display (c) an LED (d) a buzzer
19. 19.🌐 A soil sensor sends a reading to an app every 20 minutes. How many readings arrive in 1 hour?
20. 20.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
21. 21.True or false: to tap unknown app links is a risky habit. (a) True (b) False
22. 22.🔦 A circuit has a new cell, a bulb with a broken filament and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a glass marble. Does the bulb glow? (a) Yes (b) No
23. 23.⚡ A home appliance on the 230 V mains takes 1.5 A. What is its power (in watts)?
24. 24.🔺 A current of 10 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
25. 25.Which of these is an IoT device? (a) a pencil sharpener (b) a plain wall switch (c) a paper calendar (d) a fitness band with app
26. 26.🔘 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 OFF and C is OFF. Does the bulb glow? (a) Yes (b) No
27. 27.🧮 A 10 Ω resistor is joined in series with two equal 50 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
28. 28.⚡ What do we call a flow of electric charge through a wire? (a) friction (b) a magnet (c) sound (d) electric current
29. 29.🔋 8 identical 1.5 V cells are joined in series (+ of one cell to − of the next). What is the total voltage (in volts)? =
30. 30.💡 An LED (with its resistor) is on pin 8. All pins start LOW. The program runs once:
    set pin 8 LOW
    set pin 8 HIGH
    set pin 7 HIGH
    Is the LED ON or OFF at the end? (a) OFF (b) ON
31. 31.⚠️ Why must we never touch switches with wet hands? (a) it spoils the paint (b) water makes it cold (c) it is just untidy (d) water carries current
32. 32.🔺 A current of 20 mA flows when 5 V is joined across a resistor. What is its resistance (in ohms)?
33. 33.📏 How many kilowatts (kW) is 750 W? =
34. 34.🧮 Two resistors in parallel give a total that is … (a) more than either one (b) always zero (c) their sum (d) less than either one
35. 35.True or false: to cover unused cameras is a good habit. (a) True (b) False
36. 36.🔁 repeat 2 times { repeat 6 times { beep } }
    How many beeps are there?
37. 37.🧾 A 1500 W appliance runs for 4 hours. How many units (kWh) of electricity does it use? =
38. 38.True or false: to keep drinks far away is safe. (a) False (b) True
39. 39.🔋 4 identical 1.5 V cells are joined in series, but one of them is put in the wrong way round. What is the total voltage now (in volts)? =
40. 40.✏️ In a cell symbol, which line is the + terminal? (a) the shorter line (b) both lines (c) neither line (d) the longer line

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