Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 178 · 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.📏 How many kilo-ohms (kΩ) is 7400 Ω? =
2. 2.True or false: a toggle switch stays where you flip it. (a) True (b) False
3. 3.🔁 count = 4
   while (count < 8) { count = count + 2 }
   How many times does the loop run?
4. 4.Which of these is a risky habit? (a) log out of shared phones (b) post your live location (c) set up with a parent (d) install software updates
5. 5.🧮 Resistors of 33 Ω and 470 Ω are joined in series. What is the total resistance (in ohms)?
6. 6.True or false: “each gets the full volts” is true of a parallel circuit. (a) True (b) False
7. 7.What does an LDR do? (a) boosts a small signal (b) senses how bright it is (c) stores a little charge (d) limits the current
8. 8.⚡ A home appliance on the 230 V mains takes 8 A. What is its power (in watts)?
9. 9.Which of these mainly gives out heat? (a) an electric kettle (b) a torch (c) a ceiling fan (d) a doorbell
10. 10.🔋 On a cell, does “the longer symbol line” mean the + end or the − end? (a) + (positive) (b) − (negative)
11. 11.🔌 Is a steel coin a conductor or an insulator? (a) a conductor (b) an insulator
12. 12.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a cotton thread across the gap. Does the bulb glow? (a) Yes (b) No
13. 13.🔋 Cells joined + to − in a row (series) give … (a) the same voltage (b) a smaller voltage (c) no voltage (d) a bigger voltage
14. 14.True or false: to make a parking alarm, use a distance sensor. (a) False (b) True
15. 15.🔍 For a microcontroller, is a sensor an input or an output? (a) a fuse (b) a power source (c) an output (d) an input
16. 16.Which job needs a motor? (a) open a gate to 90° (b) spin a robot’s wheels (c) move water to plants (d) show a status light
17. 17.True or false: an electric kettle mainly gives out light. (a) True (b) False
18. 18.🔦 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) No (b) Yes
19. 19.🔍 Which is the odd one out? (a) a battery torch (b) a Wi-Fi smart plug (c) a plain wall switch (d) a plain table fan
20. 20.Which of these means the circuit is closed? (a) a wire has come loose (b) the switch is ON (c) a wire is cut (d) the switch is OFF
21. 21.🔘 When a switch is ON, the circuit is … (a) broken (b) cut (c) open (d) closed
22. 22.🔋 Does a cell give electricity or use electricity? (a) gives electricity (b) uses electricity
23. 23.What does a thermistor do? (a) limits the current (b) lets current go one way (c) smooths a wobbly supply (d) senses how hot it is
24. 24.✏️ In a circuit diagram, which part is drawn as a small empty box? (a) ammeter (b) resistor (c) switch (d) capacitor
25. 25.Which of these has no microcontroller inside? (a) a hand pump (b) a microwave oven (c) a TV remote (d) a washing machine
26. 26.💡 4 identical bulbs are joined in series with a 16 V battery (ideal wires). How many volts does each bulb get? =
27. 27.Which drawing is the symbol for a cell? (a) two or more cell symbols (b) a circle with a cross (c) a circle with an X in it (d) one tall, one short bar
28. 28.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
29. 29.🔁 Is the circuit closed or open if the switch is OFF? (a) closed (b) open
30. 30.🔍 A distance sensor sends a sound pulse and hears the echo 12 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?
31. 31.🔺 A current of 50 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
32. 32.🔌 Is an LED an input or an output for a microcontroller? (a) output (b) input
33. 33.🤖 Where does the board keep its program when the power is off? (a) the power LED (b) the USB cable (c) flash memory (d) the resistor
34. 34.🔺 In the V-I-R triangle, how do we find R? (a) R = V ÷ I (b) R = I ÷ V (c) R = V + I (d) R = V × I
35. 35.Which of these is not safe? (a) touch a fallen wire (b) fly kites in open fields (c) use small battery cells (d) take cells out after use
36. 36.⚡ A device works on 9 V and takes 0.1 A. What is its power (in watts)? =
37. 37.🧮 Four equal 400 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
38. 38.💡 A red LED uses 2 V and should get 25 mA. It runs from a 9 V supply. What resistor (in ohms) is needed in series?
39. 39.📏 How many ohms (Ω) is 8.9 kΩ?
40. 40.🤖 In “if (temp > 30)”, what runs when temp is exactly 30? (a) the if part (b) the else part (c) neither part (d) both parts

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