Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 303 · 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 6 V battery is joined to 4 Ω and 2 Ω resistors in series. What current flows (in amperes)? =
2. 2.🤖 if (temperature > 33) { show “Hot” } else if (temperature > 20) { show “Warm” } else { show “Cool” }
   The temperature is 15 °C. What is shown? (a) Warm (b) Hot (c) Cool
3. 3.True or false: to open blinds at sunrise, use a distance sensor. (a) False (b) True
4. 4.🔘 Two switches are in parallel (side by side). When does the bulb glow? (a) only when both are ON (b) never (c) only when both are OFF (d) when either is ON
5. 5.True or false: on an LED, the shorter leg is the anode (+). (a) True (b) False
6. 6.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the filament (b) the base (c) the switch (d) the glass
7. 7.True or false: “a single current path” is true of a parallel circuit. (a) True (b) False
8. 8.Which of these has no microcontroller inside? (a) a digital alarm clock (b) a plain wall switch (c) a smart watch (d) a digital thermometer
9. 9.🤖 if (temperature > 33) { show “Hot” } else if (temperature > 19) { show “Warm” } else { show “Cool” }
   The temperature is 29 °C. What is shown? (a) Warm (b) Hot (c) Cool
10. 10.🔋 On a cell, does “the longer symbol line” mean the + end or the − end? (a) − (negative) (b) + (positive)
11. 11.⚠️ About how many volts do home sockets in India supply? (a) 1.5 V (b) 9 V (c) 12 V (d) 230 V
12. 12.🔺 A current of 25 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
13. 13.⚠️ Is it safe to throw cells in a fire? (a) not safe (b) safe
14. 14.🔁 Is the circuit closed or open if a wire has come loose? (a) closed (b) open
15. 15.🌐 Is a plain table fan an IoT device? (a) not an IoT device (b) an IoT device
16. 16.🔋 3 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)? =
17. 17.💡 Old festival light strings went fully dark when one bulb failed. How were they joined? (a) in series (b) by Wi-Fi (c) in parallel (d) not joined
18. 18.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
19. 19.⏱️ loop forever { LED ON; wait 50 ms; LED OFF; wait 150 ms }
    How many times does the LED blink in 4 seconds?
20. 20.True or false: “how bright a room is” is a digital signal. (a) False (b) True
21. 21.💡 An LED is joined to a 9 V battery through a 1000 Ω resistor; the leg next to the flat edge of its rim goes to the + side. What happens? (a) lights up (b) may burn out (c) does not light
22. 22.🧮 Two resistors in parallel give a total that is … (a) always zero (b) their sum (c) less than either one (d) more than either one
23. 23.🔺 In the V-I-R triangle, how do we find V? (a) V = R ÷ I (b) V = I ÷ R (c) V = I + R (d) V = I × R
24. 24.True or false: on a cell, “the flat end” means the − (negative) end. (a) False (b) True
25. 25.🔌 Is an LED an input or an output for a microcontroller? (a) input (b) output
26. 26.Which drawing is the symbol for a resistor? (a) a dot where wires meet (b) a plain rectangle (c) a circle with V inside (d) triangle against a bar
27. 27.⏱️ How many milliseconds is a wait of 0.8 seconds?
28. 28.🧾 One “unit” on an electricity bill is … (a) 1 ampere (b) 1 volt (c) 1 kilowatt-hour (kWh) (d) 1 watt
29. 29.🌈 Which band is read first on a resistor? (a) the one nearest an end (b) the widest gap (c) any band (d) the gold band
30. 30.💡 5 identical bulbs are in parallel and each bulb has its own switch on its path. 2 of the switches are OFF and the rest are ON. How many bulbs glow?
31. 31.Which of these gives us electricity? (a) a cell (b) a mobile phone (c) an air conditioner (d) a washing machine
32. 32.🔁 x = 1
    repeat 2 times { x = x × 2 }
    What is x at the end?
33. 33.🧮 A 7 V battery is joined to 2 Ω and 12 Ω resistors in series. What current flows (in amperes)? =
34. 34.🧾 A 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 6 hours. How many watt-hours (Wh) are saved?
35. 35.🔁 count = 3
    while (count < 12) { count = count + 3 }
    How many times does the loop run?
36. 36.🔁 Is the circuit closed or open if a wire is cut? (a) closed (b) open
37. 37.⚡ A device works on 9 V and takes 1 A. What is its power (in watts)? =
38. 38.True or false: on an LED, the longer leg is the cathode (−). (a) True (b) False
39. 39.🌈 A resistor has the colour bands grey, white, red. What is its value in kilo-ohms (kΩ)? =
40. 40.🔺 A current of 25 mA flows through a 500 Ω resistor. What is the voltage across it (in volts)? =

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