Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 136 · 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 current of 0.25 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
2. 2.🔋 Cells joined + to − in a row (series) give … (a) no voltage (b) the same voltage (c) a smaller voltage (d) a bigger voltage
3. 3.🔁 x = 5
   repeat 2 times { x = x × 2 }
   What is x at the end?
4. 4.📏 Voltmeter or ammeter: which one measures current? (a) ammeter (b) voltmeter
5. 5.🔁 Is the circuit closed or open if the loop is complete? (a) open (b) closed
6. 6.🤖 if (light < 200) { lamp ON } else { lamp OFF }
   The light sensor reads 200. What happens? (a) lamp OFF (b) lamp ON
7. 7.🔍 Which is the odd one out? (a) the pump turns on (b) a buzzer beeps (c) an alert on the phone (d) check if temp > 30
8. 8.Which of these is not an IoT device? (a) a smart energy meter (b) a Wi-Fi smart plug (c) a Wi-Fi doorbell camera (d) a paper calendar
9. 9.⚡ An 18 W device works on 6 V. What current does it take (in amperes)? =
10. 10.True or false: a tilt switch closes when tipped over. (a) False (b) True
11. 11.🔘 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 OFF. Does the bulb glow? (a) No (b) Yes
12. 12.🔗 Series or parallel circuit: “a break stops every bulb”? (a) series (b) parallel
13. 13.🤖 if (moisture < 50) { pump ON } else { pump OFF }
    The soil moisture sensor reads 30 %. What happens? (a) pump ON (b) pump OFF
14. 14.🔍 Which is the odd one out? (a) a light sensor (b) a small display (c) a keypad (d) a sound sensor
15. 15.⏱️ repeat 10 times { buzzer ON; wait 700 ms; buzzer OFF; wait 400 ms }
    How many milliseconds does this take in all?
16. 16.🔺 A current of 25 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
17. 17.🔁 x = 2
    repeat 2 times { x = x × 2 }
    What is x at the end?
18. 18.🔍 Which is the odd one out? (a) share only needed data (b) change default passwords (c) share the Wi-Fi key (d) log out of shared phones
19. 19.🔋 Identical cells side by side (in parallel) give … (a) the same voltage (b) half the voltage (c) no voltage (d) double the voltage
20. 20.🔍 Which sensor would you use to keep an incubator warm? (a) a gas sensor (b) a rain sensor (c) a temperature sensor (d) a motion sensor
21. 21.⚠️ Is it safe to keep drinks far away? (a) safe (b) not safe
22. 22.What does a tilt switch do? (a) closes near a magnet (b) works only while pressed (c) closes when tipped over (d) slides side to side
23. 23.🌐 A soil sensor sends a reading to an app every 30 minutes. How many readings arrive in 6 hours?
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 OFF, B is OFF and C is ON. Does the bulb glow? (a) No (b) Yes
25. 25.⚠️ A cell gets hot when its + and − ends are joined by a bare wire. What is this called? (a) an open circuit (b) a short circuit (c) a parallel circuit (d) a safe circuit
26. 26.🔺 In the V-I-R triangle, how do we find I? (a) I = V ÷ R (b) I = R ÷ V (c) I = V + R (d) I = V × R
27. 27.⏱️ loop forever { LED ON; wait 850 ms; LED OFF; wait 650 ms }
    How many milliseconds does one blink (ON + OFF) take?
28. 28.🌈 A gold fourth band on a resistor means the value may be off by … (a) 25 % (b) 5 % (c) 50 % (d) 0 %
29. 29.🔺 In the V-I-R triangle, how do we find V? (a) V = I ÷ R (b) V = I + R (c) V = I × R (d) V = R ÷ I
30. 30.✏️ In a circuit diagram, which part is drawn as a dot where wires meet? (a) voltmeter (b) resistor (c) junction (d) cell
31. 31.🌈 A resistor has the colour bands brown, black, brown. What is its value (in ohms)?
32. 32.True or false: on an LED, the longer leg is the cathode (−). (a) False (b) True
33. 33.🔺 A current of 0.2 A flows when 1 V is joined across a resistor. What is its resistance (in ohms)?
34. 34.🧮 Three equal 15 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
35. 35.🔁 repeat 2 times { repeat 6 times { beep } }
    How many beeps are there?
36. 36.True or false: to make a parking alarm, use a distance sensor. (a) True (b) False
37. 37.💡 An LED (with its resistor) is on pin 8. All pins start LOW. The program runs once:
    set pin 8 HIGH
    set pin 7 LOW
    set pin 7 HIGH
    set pin 7 LOW
    set pin 7 HIGH
    Is the LED ON or OFF at the end? (a) ON (b) OFF
38. 38.Which of these is true of a series circuit? (a) own switch for each bulb (b) one bulb out, all go out (c) one out, the rest glow (d) used in house wiring
39. 39.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 31 Ω resistor? (a) brown-orange-black (b) yellow-brown-black (c) orange-brown-black (d) orange-brown-brown
40. 40.🌈 A resistor has the colour bands brown, red, black. What is its value (in ohms)?

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