Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 121 · 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 capacitor in a circuit can … (a) spin a wheel (b) measure heat (c) make light (d) store charge briefly
2. 2.🔗 Series or parallel circuit: “many paths for current”? (a) series (b) parallel
3. 3.💡 Why is house wiring done in parallel? (a) to make bulbs dim (b) to save copper only (c) so all go off together (d) each gets full voltage
4. 4.🔗 Series or parallel circuit: “one out, the rest glow”? (a) series (b) parallel
5. 5.True or false: many long-short pairs is the symbol for a cell. (a) True (b) False
6. 6.🔐 Is it a good or a risky habit to set up with a parent? (a) risky habit (b) good habit
7. 7.📶 On a 5 V board, a pin set HIGH gives about … (a) 0 V (b) 5 V (c) 230 V (d) 50 V
8. 8.🔍 Which is the odd one out? (a) poke things in a socket (b) fly a kite near wires (c) touch a fallen wire (d) fly kites in open fields
9. 9.🧮 A 20 Ω resistor is joined in series with two equal 220 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
10. 10.🌈 A resistor has the colour bands red, brown, yellow. What is its value in kilo-ohms (kΩ)? =
11. 11.🧩 Which component beeps for an alarm? (a) diode (b) transistor (c) buzzer (d) capacitor
12. 12.Which drawing is the symbol for a wire? (a) two or more cell symbols (b) a straight line (c) a small empty box (d) a plain rectangle
13. 13.🤖 Microcontroller or laptop: which one uses very little power? (a) microcontroller (b) laptop
14. 14.What does a toggle switch do? (a) flips up or down (b) slides side to side (c) closes near a magnet (d) closes when tipped over
15. 15.Which of these means the circuit is open? (a) the switch is ON (b) all wires are joined (c) a wire has come loose (d) the loop is complete
16. 16.Which of these mainly makes sound? (a) a doorbell (b) a mixer grinder (c) a water heater (d) an electric iron
17. 17.🔺 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
18. 18.🔍 Which is the odd one out? (a) a soil moisture reading (b) a temperature reading (c) a light level reading (d) check if temp > 30
19. 19.⏱️ loop forever { LED ON; wait 150 ms; LED OFF; wait 100 ms }
    How many times does the LED blink in 10 seconds?
20. 20.🔺 A 15 V supply is joined across a 300 Ω resistor. What current flows (in milliamperes, mA)?
21. 21.⚡ A home appliance on the 230 V mains takes 4 A. What is its power (in watts)?
22. 22.Which job needs a light sensor? (a) start a fan when hot (b) open blinds at sunrise (c) stop a robot near walls (d) measure classroom noise
23. 23.🔌 Is a turning knob an input or an output for a microcontroller? (a) output (b) input
24. 24.✏️ Why do engineers draw circuits with symbols? (a) quick and clear for all (b) to hide the circuit (c) to make it colourful (d) symbols are heavier
25. 25.🔍 Which is the odd one out? (a) leave the TV on standby (b) use old filament bulbs (c) use LED lamps (d) leave fridge door open
26. 26.🔦 A circuit has a used-up (dead) cell, a good bulb and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a metal paper clip. Does the bulb glow? (a) Yes (b) No
27. 27.Which of these means the circuit is open? (a) all wires are joined (b) the switch is ON (c) the loop is complete (d) a wire is cut
28. 28.True or false: on a cell, “the flat end” means the − (negative) end. (a) False (b) True
29. 29.🔘 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?
30. 30.🔍 Which is the odd one out? (a) a servo motor (b) a speaker (c) a temperature sensor (d) a small display
31. 31.💡 2 identical bulbs are joined in series with a 4 V battery (ideal wires). How many volts does each bulb get? =
32. 32.⚡ A home appliance on the 230 V mains takes 1 A. What is its power (in watts)?
33. 33.🔌 Which metal is used for most electric wires at home? (a) glass (b) rubber (c) plastic (d) copper
34. 34.🤖 if (temperature > 37) { show “Hot” } else if (temperature > 22) { show “Warm” } else { show “Cool” }
    The temperature is 23 °C. What is shown? (a) Hot (b) Warm (c) Cool
35. 35.💡 In a series circuit, how many paths does the current have? (a) one for each bulb (b) one (c) none (d) two
36. 36.💡 5 identical bulbs are joined in series with a battery and a closed switch on the main wire. Bulb 4 is taken out of its holder. Does bulb 2 glow? (a) Yes (b) No
37. 37.True or false: a school bell mainly gives out heat. (a) True (b) False
38. 38.🔺 A 7.5 V supply is joined across a 150 Ω resistor. What current flows (in milliamperes, mA)?
39. 39.🔘 A cell and a bulb are joined to 4 side-by-side paths with one switch on each path — A, B, C and D (parallel). A is ON, B is ON, C is OFF and D is ON. Does the bulb glow? (a) No (b) Yes
40. 40.🔺 A current of 0.2 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =

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