Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 647 · 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 blue LED uses 3 V and should get 20 mA. It runs from a 9 V supply. What resistor (in ohms) is needed in series?
2. 2.True or false: to cover unused cameras is a good habit. (a) True (b) False
3. 3.True or false: a capacitor is a resistance knob. (a) False (b) True
4. 4.⚡ Which formula gives electric power? (a) P = V ÷ I (b) P = V + I (c) P = V × I (d) P = I ÷ V
5. 5.⚡ A home appliance on the 230 V mains takes 1.5 A. What is its power (in watts)?
6. 6.What does a toggle switch do? (a) stays where you flip it (b) slides side to side (c) closes near a magnet (d) springs back when let go
7. 7.⚠️ Is it safe to keep drinks far away? (a) not safe (b) safe
8. 8.🤖 “if (A AND B)” is true when … (a) only B is true (b) both A and B are true (c) only A is true (d) both are false
9. 9.True or false: on a cell, “usually the black wire” means the − (negative) end. (a) False (b) True
10. 10.🔍 Which is the odd one out? (a) a smart energy meter (b) a fitness band with app (c) a plain table fan (d) a Wi-Fi doorbell camera
11. 11.What does a tilt switch do? (a) works only while pressed (b) flips up or down (c) stays where you flip it (d) closes when tipped over
12. 12.🧩 Which component makes a beeping sound? (a) motor (b) resistor (c) buzzer (d) potentiometer
13. 13.Which of these means the circuit is closed? (a) a wire has come loose (b) the loop is complete (c) a wire is cut (d) the bulb is unscrewed
14. 14.📏 How many amperes (A) is 920 mA? =
15. 15.🔋 5 identical 2 V cells are joined side by side in parallel (all + ends together, all − ends together). What is the voltage across them (in volts)? =
16. 16.🔌 Is a sound sensor an input or an output for a microcontroller? (a) output (b) input
17. 17.Which of these is a conductor? (a) a glass marble (b) a rubber eraser (c) a copper wire (d) a woollen thread
18. 18.🔁 repeat 5 times { repeat 6 times { beep } }
    How many beeps are there?
19. 19.📏 How many milliamperes (mA) is 2.62 A?
20. 20.🌈 A resistor has the colour bands orange, brown, red. What is its value in kilo-ohms (kΩ)? =
21. 21.🔍 Which is the odd one out? (a) a speaker (b) a light sensor (c) a keypad (d) a sound sensor
22. 22.⏱️ A program says “wait 2250 ms”. How many seconds is that? =
23. 23.True or false: one tall, one short bar is the symbol for a cell. (a) False (b) True
24. 24.🌈 A resistor has the colour bands orange, orange, red. What is its value in kilo-ohms (kΩ)? =
25. 25.📏 How many kilowatts (kW) is 4000 W? =
26. 26.🔘 A bulb and a cell are joined through 6 switches on 6 side-by-side paths, one switch on each path (parallel). What is the smallest number of switches that must be ON to light the bulb?
27. 27.True or false: an iron nail is a conductor. (a) False (b) True
28. 28.🔋 A 9 V battery and three 1.5 V cells are joined in series, all facing the same way. What is the total voltage (in volts)? =
29. 29.✏️ In a circuit diagram, which part is drawn as a circle with an X in it? (a) bulb (b) LED (c) battery (d) diode
30. 30.🤖 if (light < 300 OR motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 630 and motion is not detected (false). What happens? (a) porch lamp ON (b) porch lamp OFF
31. 31.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
32. 32.True or false: a room heater mainly gives out light. (a) False (b) True
33. 33.💡 Does it save or waste electricity to unplug idle chargers? (a) saves electricity (b) wastes electricity
34. 34.💡 An LED (with its resistor) is on pin 7. All pins start LOW. The program runs once:
    set pin 7 HIGH
    set pin 7 LOW
    set pin 7 LOW
    set pin 7 HIGH
    Is the LED ON or OFF at the end? (a) OFF (b) ON
35. 35.🔗 Series or parallel circuit: “many paths for current”? (a) parallel (b) series
36. 36.🔋 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)? =
37. 37.🤖 if (light < 300 OR motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 170 and motion is not detected (false). What happens? (a) porch lamp OFF (b) porch lamp ON
38. 38.🔘 When a switch is ON, the circuit is … (a) broken (b) open (c) cut (d) closed
39. 39.🔺 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
40. 40.🗺️ In an input → process → output plan, is “an alert on the phone” the input, the process or the output? (a) input (b) output (c) process

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