Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 880 · 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.Which of these mainly makes sound? (a) a buzzer (b) a traffic signal (c) a table fan (d) a mixer grinder
2. 2.🔋 Identical cells side by side (in parallel) give … (a) double the voltage (b) no voltage (c) the same voltage (d) half the voltage
3. 3.True or false: to build with an adult near is not safe. (a) True (b) False
4. 4.🔋 A 12 V battery and one 1.5 V cell are joined in series, all facing the same way. What is the total voltage (in volts)? =
5. 5.🌈 A resistor has the colour bands orange, yellow, yellow. What is its value in kilo-ohms (kΩ)? =
6. 6.True or false: a tilt switch works only while pressed. (a) False (b) True
7. 7.🌈 A resistor has the colour bands orange, yellow, orange. What is its value (in ohms)?
8. 8.📏 Which unit measures voltage? (a) ohm (Ω) (b) ampere (A) (c) volt (V) (d) watt (W)
9. 9.🔐 Is it a good or a risky habit to tap unknown app links? (a) good habit (b) risky habit
10. 10.True or false: to share camera links is a risky habit. (a) True (b) False
11. 11.💡 6 identical bulbs are joined in parallel (each on its own side-by-side path) with a battery and a closed switch on the main wire. Bulbs 3 and 4 are taken out of their holders. How many bulbs glow?
12. 12.🔘 A cell, a bulb and switches A, B, C and D are joined one after another in a single loop (series). A is OFF, B is OFF, C is OFF and D is ON. Does the bulb glow? (a) Yes (b) No
13. 13.🔺 A 0.5 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =
14. 14.Which of these mainly gives out heat? (a) a siren (b) a doorbell (c) a school bell (d) a water heater
15. 15.True or false: on a cell, “the end with a bump” means the − (negative) end. (a) True (b) False
16. 16.🔋 How many volts does one ordinary torch cell give? (a) 0.5 V (b) 230 V (c) 1.5 V (d) 15 V
17. 17.💡 An LED (with its resistor) is on pin 7. All pins start LOW. The program runs once:
    set pin 8 LOW
    set pin 8 LOW
    set pin 8 LOW
    set pin 7 LOW
    set pin 7 HIGH
    Is the LED ON or OFF at the end? (a) ON (b) OFF
18. 18.🧮 A 4.8 V battery is joined to 12 Ω and 12 Ω resistors in series. What current flows (in amperes)? =
19. 19.Which of these is safe? (a) throw cells in a fire (b) poke things in a socket (c) build with an adult near (d) touch a fallen wire
20. 20.🔐 Is it a good or a risky habit to cover unused cameras? (a) risky habit (b) good habit
21. 21.Which of these means the circuit is closed? (a) the switch is OFF (b) a cell is taken out (c) the bulb is unscrewed (d) all wires are joined
22. 22.🔌 Is a water pump an input or an output for a microcontroller? (a) input (b) output
23. 23.🔺 A 3 V supply is joined across a 150 Ω resistor. What current flows (in milliamperes, mA)?
24. 24.⏱️ repeat 7 times { buzzer ON; wait 300 ms; buzzer OFF; wait 500 ms }
    How many milliseconds does this take in all?
25. 25.🔍 Which is the odd one out? (a) use LED lamps (b) run fans in empty rooms (c) leave the TV on standby (d) use old filament bulbs
26. 26.🧮 Two equal 10 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
27. 27.What does a slide switch do? (a) closes when tipped over (b) slides side to side (c) springs back when let go (d) closes near a magnet
28. 28.⚡ A 4.5 W device works on 3 V. What current does it take (in amperes)? =
29. 29.Which of these is safe? (a) poke things in a socket (b) fly a kite near wires (c) touch a switch when wet (d) use small battery cells
30. 30.⚠️ Which power source should children use for electronics projects? (a) an inverter socket (b) a wall socket (c) a small battery pack (d) a mains extension board
31. 31.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) stays the same (b) gets bigger (c) gets smaller (d) becomes zero
32. 32.⏱️ loop forever { LED ON; wait 100 ms; LED OFF; wait 900 ms }
    How many times does the LED blink in 2 seconds?
33. 33.🌈 A resistor has the colour bands yellow, violet, red. What is its value in kilo-ohms (kΩ)? =
34. 34.🔺 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
35. 35.True or false: to fly kites in open fields is safe. (a) True (b) False
36. 36.🔘 Which kind of switch springs back when let go? (a) a slide switch (b) a push button (c) a toggle switch (d) a reed switch
37. 37.💡 A red LED (it uses 2 V) is joined with a 100 Ω resistor to a 3.5 V supply. What current flows (in mA)?
38. 38.⚡ Power tells us … (a) the colour of light (b) the length of a wire (c) the size of a cell (d) energy used each second
39. 39.⚡ A device works on 3 V and takes 0.25 A. What is its power (in watts)? =
40. 40.🗺️ In an input → process → output plan, is “a button press” the input, the process or the output? (a) output (b) input (c) process

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