Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 348 · 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.🌐 In an IoT system, which part carries the data? (a) Wi-Fi (b) sensor (c) microcontroller (d) phone app
2. 2.⚠️ Is it safe to throw cells in a fire? (a) not safe (b) safe
3. 3.🔋 Does a solar panel give electricity or use electricity? (a) uses electricity (b) gives electricity
4. 4.⚠️ Which power source should children use for electronics projects? (a) a small battery pack (b) a mains extension board (c) an inverter socket (d) a wall socket
5. 5.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
6. 6.🔘 A cell and a bulb are joined to 3 side-by-side paths with one switch on each path — A, B and C (parallel). A is ON, B is OFF and C is OFF. Does the bulb glow? (a) No (b) Yes
7. 7.💡 What happens if an LED is put in backwards? (a) it does not light (b) it changes colour (c) it lights brighter (d) it makes a sound
8. 8.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a dry cork across the gap. Does the bulb glow? (a) No (b) Yes
9. 9.📏 Which unit measures current? (a) volt (V) (b) ampere (A) (c) watt (W) (d) ohm (Ω)
10. 10.🔺 A current of 10 mA flows through a 500 Ω resistor. What is the voltage across it (in volts)? =
11. 11.🤖 if (light < 200 AND motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 160 and motion is detected (true). What happens? (a) porch lamp ON (b) porch lamp OFF
12. 12.Which of these means the circuit is open? (a) the loop is complete (b) all wires are joined (c) a wire is cut (d) the switch is ON
13. 13.🌈 A resistor has the colour bands blue, black, red. What is its value in kilo-ohms (kΩ)? =
14. 14.🗺️ In an input → process → output plan, is “compare with a limit” the input, the process or the output? (a) process (b) input (c) output
15. 15.⏱️ repeat 8 times { buzzer ON; wait 600 ms; buzzer OFF; wait 900 ms }
    How many milliseconds does this take in all?
16. 16.🔋 3 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)? =
17. 17.⚠️ Why must we never touch switches with wet hands? (a) water makes it cold (b) water carries current (c) it spoils the paint (d) it is just untidy
18. 18.🔁 count = 3
    repeat 7 times { count = count + 10 }
    What is count at the end?
19. 19.🧾 A family uses 30 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
20. 20.🌈 A resistor has the colour bands blue, red, red. What is its value in kilo-ohms (kΩ)? =
21. 21.🔍 Which is the odd one out? (a) a rubber band (b) a brass key (c) a dry cork (d) a cotton thread
22. 22.🔁 total = 0
    for i = 1 to 11 { total = total + i }
    What is total at the end?
23. 23.⚙️ Which actuator would you use to beep an alarm? (a) a buzzer (b) a pump (c) a display (d) a servo motor
24. 24.⏱️ loop forever { LED ON; wait 100 ms; LED OFF; wait 400 ms }
    How many milliseconds does one blink (ON + OFF) take?
25. 25.🔦 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
26. 26.🌈 A resistor has the colour bands orange, red, orange. What is its value in kilo-ohms (kΩ)? =
27. 27.🔺 A current of 25 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
28. 28.🧩 Which component senses how hot it is? (a) motor (b) thermistor (c) transistor (d) LED
29. 29.💡 5 identical bulbs are joined in series with a 10 V battery (ideal wires). How many volts does each bulb get? =
30. 30.⚠️ Is it safe to use small battery cells? (a) not safe (b) safe
31. 31.True or false: to open a phone charger is safe. (a) True (b) False
32. 32.🔺 A current of 0.2 A flows when 0.4 V is joined across a resistor. What is its resistance (in ohms)?
33. 33.🔍 A distance sensor sends a sound pulse and hears the echo 17 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?
34. 34.True or false: to keep an incubator warm, use a sound sensor. (a) False (b) True
35. 35.🧾 One “unit” on an electricity bill is … (a) 1 volt (b) 1 kilowatt-hour (kWh) (c) 1 ampere (d) 1 watt
36. 36.🔘 A bulb and a cell are joined through 4 switches one after another in a single loop (series). What is the smallest number of switches that must be ON to light the bulb?
37. 37.True or false: a reed switch springs back when let go. (a) True (b) False
38. 38.💡 An LED is joined to a 6 V battery through a 220 Ω resistor; the leg next to the flat edge of its rim goes to the − side. What happens? (a) does not light (b) lights up (c) may burn out
39. 39.True or false: one tall, one short bar is the symbol for an LED. (a) True (b) False
40. 40.🔁 A bulb has two contacts. How many must be joined into the loop for it to glow? (a) only one (b) it does not matter (c) both of them (d) none

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