Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 953 · 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.🔁 count = 3
   while (count < 15) { count = count + 3 }
   How many times does the loop run?
2. 2.🔌 Is a plastic straw a conductor or an insulator? (a) a conductor (b) an insulator
3. 3.🧮 A 2 V battery is joined to 10 Ω and 10 Ω resistors in series. What current flows (in amperes)? =
4. 4.💡 An LED (with its resistor) is on pin 8. All pins start LOW. The program runs once:
   set pin 8 HIGH
   set pin 7 LOW
   set pin 7 HIGH
   Is the LED ON or OFF at the end? (a) OFF (b) ON
5. 5.🔋 How many 1.2 V cells must be joined in series to give 7.2 V?
6. 6.💡 5 identical bulbs are joined in series with a 5 V battery (ideal wires). How many volts does each bulb get? =
7. 7.💡 A red LED uses 2 V and should get 25 mA. It runs from a 12 V supply. What resistor (in ohms) is needed in series?
8. 8.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
9. 9.🔋 Does a television give electricity or use electricity? (a) uses electricity (b) gives electricity
10. 10.Which job needs a soil moisture sensor? (a) keep an incubator warm (b) switch on lamps at dusk (c) make a parking alarm (d) water a dry plant
11. 11.📏 How many watts (W) is 0.3 kW?
12. 12.🔺 A current of 20 mA flows through a 250 Ω resistor. What is the voltage across it (in volts)? =
13. 13.🔘 A bulb and a cell are joined through 2 switches on 2 side-by-side paths, one switch on each path (parallel). What is the smallest number of switches that must be ON to light the bulb?
14. 14.📶 Digital or analog: HIGH or LOW only? (a) digital (b) analog
15. 15.⏱️ A program says “wait 7000 ms”. How many seconds is that? =
16. 16.True or false: on a cell, “the end with a bump” means the + (positive) end. (a) False (b) True
17. 17.📏 Which unit measures power? (a) volt (V) (b) ampere (A) (c) ohm (Ω) (d) watt (W)
18. 18.🔋 6 identical 1.5 V cells are joined in series (+ of one cell to − of the next). What is the total voltage (in volts)? =
19. 19.Which of these mainly gives out light? (a) a street light (b) a loudspeaker (c) an electric kettle (d) a siren
20. 20.🔺 A 10 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
21. 21.💡 2 identical bulbs are in parallel and each one takes 0.2 A. What total current (in amperes) comes from the battery? =
22. 22.True or false: a potentiometer glows using little power. (a) True (b) False
23. 23.🔋 On a cell, does “usually the black wire” mean the + end or the − end? (a) − (negative) (b) + (positive)
24. 24.💡 In a series circuit, how many paths does the current have? (a) two (b) none (c) one (d) one for each bulb
25. 25.Which of these means the circuit is closed? (a) the switch is OFF (b) the switch is ON (c) a wire has come loose (d) a wire is cut
26. 26.💡 Old festival light strings went fully dark when one bulb failed. How were they joined? (a) by Wi-Fi (b) not joined (c) in series (d) in parallel
27. 27.🔍 Which sensor would you use to water a dry plant? (a) a sound sensor (b) a soil moisture sensor (c) a distance sensor (d) a light sensor
28. 28.True or false: if a cell is taken out, the circuit is open and no current flows. (a) True (b) False
29. 29.🌈 A gold fourth band on a resistor means the value may be off by … (a) 50 % (b) 5 % (c) 0 % (d) 25 %
30. 30.True or false: “a break stops every bulb” is true of a series circuit. (a) False (b) True
31. 31.🧾 One “unit” on an electricity bill is … (a) 1 ampere (b) 1 volt (c) 1 kilowatt-hour (kWh) (d) 1 watt
32. 32.⏱️ How many milliseconds is a wait of 3.6 seconds?
33. 33.Which of these is measured in amperes (A)? (a) power (b) the push of a cell (c) voltage (d) current
34. 34.🔺 A current of 2 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
35. 35.💡 Does it save or waste electricity to use daylight to read? (a) saves electricity (b) wastes electricity
36. 36.🔋 Identical cells side by side (in parallel) give … (a) double the voltage (b) no voltage (c) the same voltage (d) half the voltage
37. 37.True or false: a microcontroller runs one small program. (a) True (b) False
38. 38.🧩 Which component makes things spin? (a) LED (b) motor (c) capacitor (d) buzzer
39. 39.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a paper strip across the gap. Does the bulb glow? (a) No (b) Yes
40. 40.✏️ Why do engineers draw circuits with symbols? (a) to make it colourful (b) quick and clear for all (c) to hide the circuit (d) symbols are heavier

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