Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 642 · 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.💡 2 identical bulbs are joined in parallel across a 6 V battery (ideal wires). How many volts does each bulb get? =
2. 2.🧮 Three equal 30 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
3. 3.🔺 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
4. 4.True or false: to throw cells in a fire is safe. (a) True (b) False
5. 5.💡 4 identical bulbs are joined in series with a 4 V battery (ideal wires). How many volts does each bulb get? =
6. 6.⚡ A device works on 6 V and takes 0.2 A. What is its power (in watts)? =
7. 7.Which job needs a light sensor? (a) spot someone walking in (b) start a fan when hot (c) switch on lamps at dusk (d) water a dry plant
8. 8.True or false: if the switch is ON, the circuit is closed and current flows. (a) True (b) False
9. 9.💡 Does it save or waste electricity to run fans in empty rooms? (a) wastes electricity (b) saves electricity
10. 10.🔌 Is a motion sensor an input or an output for a microcontroller? (a) input (b) output
11. 11.🔺 In the V-I-R triangle, how do we find R? (a) R = V + I (b) R = V ÷ I (c) R = V × I (d) R = I ÷ V
12. 12.What does the sensor do? (a) measures the real world (b) shows data to you (c) reads values, decides (d) acts on a command
13. 13.💡 A blue LED uses 3 V and should get 10 mA. It runs from a 5 V supply. What resistor (in ohms) is needed in series?
14. 14.🔍 Which is the odd one out? (a) an LED (b) a keypad (c) a motor (d) a buzzer
15. 15.🔺 A current of 1 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
16. 16.Which of these is safe? (a) touch a switch when wet (b) use small battery cells (c) use mains for a project (d) open a phone charger
17. 17.🔌 Is a plastic straw a conductor or an insulator? (a) an insulator (b) a conductor
18. 18.🤖 “if (A AND B)” is true when … (a) both A and B are true (b) only B is true (c) both are false (d) only A is true
19. 19.⏱️ loop forever { LED ON; wait 100 ms; LED OFF; wait 150 ms }
    How many times does the LED blink in 1 second?
20. 20.🌈 A resistor has the colour bands yellow, grey, brown. What is its value (in ohms)?
21. 21.💡 6 identical bulbs are joined in series with a battery and a closed switch on the main wire. Bulb 1 is taken out of its holder. Does bulb 2 glow? (a) Yes (b) No
22. 22.Which of these means the circuit is open? (a) the switch is ON (b) the loop is complete (c) the switch is OFF (d) all wires are joined
23. 23.⚠️ Is it safe to keep drinks far away? (a) safe (b) not safe
24. 24.💡 A battery lights 2 identical bulbs joined in series. One more identical bulb is added in series. How do the bulbs glow now? (a) the same (b) brighter (c) dimmer
25. 25.🔋 On a cell, does “the flat end” mean the + end or the − end? (a) + (positive) (b) − (negative)
26. 26.📏 How many watts (W) is 2.7 kW?
27. 27.🔘 Which kind of switch springs back when let go? (a) a tilt switch (b) a slide switch (c) a push button (d) a reed switch
28. 28.True or false: a circle with A inside is the symbol for an ammeter. (a) False (b) True
29. 29.🔍 Which is the odd one out? (a) count button presses (b) the fan starts (c) a buzzer beeps (d) an LED lights up
30. 30.What does the cloud server do? (a) carries the data (b) acts on a command (c) measures the real world (d) stores data online
31. 31.⚡ What does an electric iron mainly change electricity into? (a) movement (b) sound (c) light (d) heat
32. 32.💡 3 identical bulbs are joined in series with a 9 V battery (ideal wires). How many volts does each bulb get? =
33. 33.📏 How many milliamperes (mA) is 0.46 A?
34. 34.🔋 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)? =
35. 35.⚡ A device works on 3 V and takes 3 A. What is its power (in watts)? =
36. 36.💡 Does it save or waste electricity to close the fridge quickly? (a) saves electricity (b) wastes electricity
37. 37.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 24000 Ω resistor? (a) red-yellow-orange (b) yellow-red-orange (c) red-yellow-yellow (d) red-yellow-red
38. 38.🔗 Series or parallel circuit: “one out, the rest glow”? (a) series (b) parallel
39. 39.🔗 Series or parallel circuit: “a single current path”? (a) series (b) parallel
40. 40.True or false: “one out, the rest glow” is true of a series circuit. (a) True (b) False

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