Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 34 · 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.🔐 Is it a good or a risky habit to cover unused cameras? (a) risky habit (b) good habit
2. 2.🔋 On a cell, does “the end with a bump” mean the + end or the − end? (a) + (positive) (b) − (negative)
3. 3.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put aluminium foil across the gap. Does the bulb glow? (a) No (b) Yes
4. 4.🔺 In the V-I-R triangle, how do we find I? (a) I = R ÷ V (b) I = V + R (c) I = V × R (d) I = V ÷ R
5. 5.⏱️ loop forever { LED ON; wait 600 ms; LED OFF; wait 1400 ms }
   How many times does the LED blink in 4 seconds?
6. 6.🔍 Which is the odd one out? (a) post your live location (b) set up with a parent (c) keep factory passwords (d) ignore update messages
7. 7.⚡ What does a night lamp mainly change electricity into? (a) sound (b) heat (c) movement (d) light
8. 8.🔺 A current of 0.5 A flows when 2 V is joined across a resistor. What is its resistance (in ohms)?
9. 9.True or false: on a cell, “the longer symbol line” means the + (positive) end. (a) True (b) False
10. 10.💡 3 identical bulbs are joined in parallel across a 1.5 V battery (ideal wires). How many volts does each bulb get? =
11. 11.⚡ A 6 W device works on 12 V. What current does it take (in amperes)? =
12. 12.🔦 A circuit has a new cell, a good bulb and a switch that is OFF. 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
13. 13.🔌 Which part of a screwdriver should an electrician hold? (a) the plastic handle (b) the bare end (c) the metal tip (d) the steel shaft
14. 14.⏱️ What does “wait 500 ms” do? (a) waits 500 seconds (b) pauses for half a second (c) blinks 500 times (d) turns the LED off
15. 15.🔍 Which is the odd one out? (a) a motion sensor signal (b) a soil moisture reading (c) count button presses (d) a temperature reading
16. 16.🔺 A 6.25 V supply is joined across a 250 Ω resistor. What current flows (in milliamperes, mA)?
17. 17.🔘 A bulb and a cell are joined through 3 switches one after another in a single loop (series). What is the smallest number of switches that must be ON to light the bulb?
18. 18.True or false: an LDR senses how bright it is. (a) True (b) False
19. 19.🔋 Does a wind turbine give electricity or use electricity? (a) gives electricity (b) uses electricity
20. 20.🔍 Which sensor would you use to open blinds at sunrise? (a) a sound sensor (b) a distance sensor (c) a soil moisture sensor (d) a light sensor
21. 21.Which of these means the circuit is open? (a) the switch is ON (b) all wires are joined (c) the loop is complete (d) a wire is cut
22. 22.Which of these is an insulator? (a) an iron nail (b) a brass key (c) a cotton thread (d) a copper wire
23. 23.Which of these is the process? (a) a light level reading (b) count button presses (c) a temperature reading (d) a buzzer beeps
24. 24.🔋 How many 1.5 V cells must be joined in series to give 7.5 V?
25. 25.🔘 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) Yes (b) No
26. 26.🔋 6 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)? =
27. 27.💡 Does it save or waste electricity to set the AC to 24 °C? (a) wastes electricity (b) saves electricity
28. 28.True or false: a toggle switch slides side to side. (a) True (b) False
29. 29.🔌 Is a cotton thread a conductor or an insulator? (a) a conductor (b) an insulator
30. 30.🔘 Which kind of switch flips up or down? (a) a toggle switch (b) a tilt switch (c) a reed switch (d) a push button
31. 31.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. Does the bulb glow? (a) Yes (b) No
32. 32.⚡ A home appliance on the 230 V mains takes 1 A. What is its power (in watts)?
33. 33.Which of these mainly makes sound? (a) a table fan (b) a traffic signal (c) a buzzer (d) an LED lamp
34. 34.🤖 Does a candle usually have a microcontroller inside? (a) No (b) Yes
35. 35.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) becomes zero (b) stays the same (c) gets bigger (d) gets smaller
36. 36.💡 An LED is joined to a 5 V battery with no resistor; its long leg goes to the + side and its short leg to the − side. What happens? (a) may burn out (b) lights up (c) does not light
37. 37.🔺 A current of 25 mA flows through a 250 Ω resistor. What is the voltage across it (in volts)? =
38. 38.True or false: to dry your hands first is not safe. (a) False (b) True
39. 39.💡 A red LED (it uses 2 V) is joined with a 200 Ω resistor to a 3 V supply. What current flows (in mA)?
40. 40.✏️ Why do engineers draw circuits with symbols? (a) quick and clear for all (b) to make it colourful (c) to hide the circuit (d) symbols are heavier

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