Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 379 · 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 gap of dry air between two wires acts as … (a) an insulator (b) a switch that is ON (c) a cell (d) a conductor
2. 2.💡 4 identical bulbs are joined in parallel across a 3 V battery (ideal wires). How many volts does each bulb get? =
3. 3.🧩 Which component lets current go one way? (a) resistor (b) diode (c) LED (d) LDR
4. 4.🔌 Is a speaker an input or an output for a microcontroller? (a) input (b) output
5. 5.🔘 Which kind of switch springs back when let go? (a) a reed switch (b) a slide switch (c) a toggle switch (d) a push button
6. 6.📶 A pin set LOW gives about … (a) 9 V (b) 5 V (c) 1.5 V (d) 0 V
7. 7.🔘 Two switches are in series. When does the bulb glow? (a) when both are ON (b) when either is ON (c) when both are OFF (d) never
8. 8.⚡ A home appliance on the 230 V mains takes 0.5 A. What is its power (in watts)?
9. 9.🔍 Which sensor would you use to start a fan when hot? (a) a temperature sensor (b) a rain sensor (c) a distance sensor (d) a sound sensor
10. 10.⚡ A device works on 1.5 V and takes 1 A. What is its power (in watts)? =
11. 11.⚡ What do we call a flow of electric charge through a wire? (a) a magnet (b) electric current (c) friction (d) sound
12. 12.🔁 What must there be for a current to flow? (a) one loose end (b) a broken path (c) a plastic gap (d) a complete loop
13. 13.⚡ A home appliance on the 230 V mains takes 1 A. What is its power (in watts)?
14. 14.🔘 When a switch is ON, the circuit is … (a) closed (b) cut (c) open (d) broken
15. 15.⏱️ What does “wait 500 ms” do? (a) turns the LED off (b) waits 500 seconds (c) blinks 500 times (d) pauses for half a second
16. 16.🔍 Which is the odd one out? (a) an electric toy car (b) a ceiling fan (c) a table fan (d) a buzzer
17. 17.Which of these mainly gives out light? (a) a table fan (b) a loudspeaker (c) a school bell (d) an LED lamp
18. 18.Which of these uses electricity? (a) a bicycle dynamo (b) a solar panel (c) a mobile phone (d) a battery
19. 19.💡 A red LED (it uses 2 V) is joined with a 300 Ω resistor to a 6.5 V supply. What current flows (in mA)?
20. 20.🔺 A current of 3 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
21. 21.💡 A battery lights 2 identical bulbs joined in parallel. One more identical bulb is added in parallel. How do the bulbs glow now? (a) the same (b) dimmer (c) brighter
22. 22.🔁 Is the circuit closed or open if the switch is ON? (a) open (b) closed
23. 23.✏️ In a circuit diagram, which part is drawn as one tall, one short bar? (a) diode (b) junction (c) voltmeter (d) cell
24. 24.What does a slide switch do? (a) springs back when let go (b) slides side to side (c) works only while pressed (d) closes when tipped over
25. 25.🔘 Which kind of switch stays where you flip it? (a) a toggle switch (b) a push button (c) a slide switch (d) a tilt switch
26. 26.💡 A red LED uses 2 V and should get 10 mA. It runs from a 9 V supply. What resistor (in ohms) is needed in series?
27. 27.True or false: a circle with an X in it is the symbol for an LED. (a) True (b) False
28. 28.True or false: “a light level reading” is the input. (a) False (b) True
29. 29.🔍 A distance sensor sends a sound pulse and hears the echo 2 ms later. Sound travels about 34 cm every millisecond. How far away is the object (in cm)?
30. 30.🔦 A circuit has a new cell, a bulb with a broken filament and a switch that is ON. All the wires are firmly joined. Does the bulb glow? (a) No (b) Yes
31. 31.🌐 A weather station sends one reading every 15 seconds. How many readings does it send in 8 minutes?
32. 32.Which of these is safe? (a) dry your hands first (b) use a cable with cuts (c) touch a switch when wet (d) throw cells in a fire
33. 33.🔋 On a cell, does “the longer symbol line” mean the + end or the − end? (a) + (positive) (b) − (negative)
34. 34.True or false: a mixer grinder mainly gives out light. (a) False (b) True
35. 35.💡 5 identical bulbs are joined in parallel (each on its own side-by-side path) with a battery and a closed switch on the main wire. Bulbs 1 and 2 are taken out of their holders. Does bulb 5 glow? (a) No (b) Yes
36. 36.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets smaller (b) becomes zero (c) gets bigger (d) stays the same
37. 37.🔺 In the V-I-R triangle, how do we find I? (a) I = V + R (b) I = V ÷ R (c) I = V × R (d) I = R ÷ V
38. 38.⚠️ About how many volts do home sockets in India supply? (a) 230 V (b) 9 V (c) 12 V (d) 1.5 V
39. 39.🔁 Is the circuit closed or open if the switch is OFF? (a) open (b) closed
40. 40.📏 Voltmeter or ammeter: which one is joined in series? (a) ammeter (b) voltmeter

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