Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 24 · 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.True or false: to use daylight to read wastes electricity. (a) True (b) False
2. 2.🔺 A 0.6 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
3. 3.🧮 Resistors of 50 Ω and 50 Ω are joined in series. What is the total resistance (in ohms)?
4. 4.🔁 count = 2
   repeat 2 times { count = count + 7 }
   What is count at the end?
5. 5.💡 A red LED (it uses 2 V) is joined with a 300 Ω resistor to a 5 V supply. What current flows (in mA)?
6. 6.🧾 One “unit” on an electricity bill is … (a) 1 ampere (b) 1 watt (c) 1 kilowatt-hour (kWh) (d) 1 volt
7. 7.🔘 A cell and a bulb are joined to 4 side-by-side paths with one switch on each path — A, B, C and D (parallel). A is OFF, B is ON, C is OFF and D is ON. Does the bulb glow? (a) Yes (b) No
8. 8.🔍 Which is the odd one out? (a) a temperature reading (b) decide if soil is dry (c) check if temp > 30 (d) compare with a limit
9. 9.Which of these is a good habit? (a) reuse one password (b) tap unknown app links (c) accept every permission (d) turn off unused gadgets
10. 10.True or false: triangle against a bar is the symbol for a wire. (a) True (b) False
11. 11.⚙️ What is an actuator? (a) a program (b) a battery (c) an output that acts (d) a sensor
12. 12.🔘 Switch A is on the main wire next to the cell and the bulb; then the wire splits into two side-by-side paths, one with switch B and one with switch C. A is ON, B is ON and C is ON. Does the bulb glow? (a) Yes (b) No
13. 13.⏱️ loop forever { LED ON; wait 300 ms; LED OFF; wait 100 ms }
    How many times does the LED blink in 14 seconds?
14. 14.🔺 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
15. 15.🔁 count = 8
    repeat 8 times { count = count + 4 }
    What is count at the end?
16. 16.🌈 In the resistor colour code, which number does red stand for?
17. 17.🔺 A current of 50 mA flows when 20 V is joined across a resistor. What is its resistance (in ohms)?
18. 18.Which of these is the input? (a) the pump turns on (b) a temperature reading (c) the fan starts (d) an alert on the phone
19. 19.True or false: a resistor limits the current. (a) True (b) False
20. 20.Which of these is an output? (a) a temperature sensor (b) a sound sensor (c) a keypad (d) a water pump
21. 21.Which of these is true of a series circuit? (a) one bulb out, all go out (b) one out, the rest glow (c) own switch for each bulb (d) each gets the full volts
22. 22.⚡ Power tells us … (a) energy used each second (b) the length of a wire (c) the size of a cell (d) the colour of light
23. 23.🔍 Which sensor would you use to warn of a gas leak? (a) a rain sensor (b) a gas sensor (c) a temperature sensor (d) a soil moisture sensor
24. 24.🔁 What does “count = count + 1” do? (a) sets count to 1 (b) adds 1 to count (c) prints 1 (d) takes 1 away
25. 25.🧮 Resistors of 22 Ω, 20 Ω, 20 Ω and 68 Ω are joined in series. What is the total resistance (in ohms)?
26. 26.🔘 Switch A is on the main wire next to the cell and the bulb; then the wire splits into two side-by-side paths, one with switch B and one with switch C. A is OFF, B is OFF and C is ON. Does the bulb glow? (a) No (b) Yes
27. 27.🧩 Which component stores a little charge? (a) fuse (b) transistor (c) capacitor (d) potentiometer
28. 28.🤖 if (light < 400 OR motion) { porch lamp ON } else { porch lamp OFF }
    The light reading is 190 and motion is not detected (false). What happens? (a) porch lamp ON (b) porch lamp OFF
29. 29.💡 4 identical bulbs are joined in parallel across a 4.5 V battery (ideal wires). How many volts does each bulb get? =
30. 30.⚡ A home appliance on the 230 V mains takes 10 A. What is its power (in watts)?
31. 31.🔗 Series or parallel circuit: “many paths for current”? (a) parallel (b) series
32. 32.🔦 A circuit has a new cell, a good bulb and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a ceramic cup. Does the bulb glow? (a) No (b) Yes
33. 33.💡 A battery lights 4 identical bulbs joined in series. One more identical bulb is added in series. How do the bulbs glow now? (a) dimmer (b) brighter (c) the same
34. 34.✏️ In a circuit diagram, which part is drawn as a plain rectangle? (a) resistor (b) motor (c) switch (d) ammeter
35. 35.🔌 A gap of dry air between two wires acts as … (a) an insulator (b) a switch that is ON (c) a conductor (d) a cell
36. 36.🔦 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
37. 37.True or false: to use a cable with cuts is safe. (a) True (b) False
38. 38.🔦 A circuit has a used-up (dead) cell, a good bulb and a switch that is ON. All the wires are firmly joined. A gap in one wire is bridged by a steel spoon. Does the bulb glow? (a) Yes (b) No
39. 39.🔦 A circuit has a new cell, a good bulb and a switch that is ON. One wire has come loose from the cell. A gap in one wire is bridged by a rubber eraser. Does the bulb glow? (a) Yes (b) No
40. 40.🔁 In an old-style bulb, which thin wire glows when current flows? (a) the base (b) the glass (c) the filament (d) the switch

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