Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 617 · 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.💡 4 identical bulbs are joined in series with a battery and a closed switch on the main wire. All the bulbs are in place. How many bulbs glow?
2. 2.🧮 Two equal 40 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
3. 3.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V + I (c) P = V × I (d) P = V ÷ I
4. 4.🔍 Which is the odd one out? (a) a cotton thread (b) a steel coin (c) a copper wire (d) an iron nail
5. 5.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets smaller (b) stays the same (c) becomes zero (d) gets bigger
6. 6.🔍 Which is the odd one out? (a) a safety pin (b) a brass key (c) a steel coin (d) a plastic ruler
7. 7.True or false: a transistor boosts a small signal. (a) False (b) True
8. 8.🔺 A 4 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
9. 9.True or false: a plastic straw is a conductor. (a) False (b) True
10. 10.🌈 A resistor has the colour bands brown, violet, red. What is its value (in ohms)?
11. 11.💡 3 identical bulbs are joined in series with a battery and a closed switch on the main wire. Bulb 1 is taken out of its holder. How many bulbs glow?
12. 12.🧩 Which part changes electrical energy into movement? (a) a motor (b) a fuse (c) an LED (d) a resistor
13. 13.⏱️ loop forever { LED ON; wait 1650 ms; LED OFF; wait 350 ms }
    How many times does the LED blink in 10 seconds?
14. 14.🔺 A current of 40 mA flows through a 120 Ω resistor. What is the voltage across it (in volts)? =
15. 15.🔌 Most metals are good … (a) magnets only (b) conductors (c) insulators (d) batteries
16. 16.True or false: a laptop runs one small program. (a) True (b) False
17. 17.What does an LED do? (a) turns a fan or wheels (b) is a resistance knob (c) senses how bright it is (d) glows using little power
18. 18.🔋 2 identical 3 V cells are joined side by side in parallel (all + ends together, all − ends together). What is the voltage across them (in volts)? =
19. 19.🌐 A soil sensor sends a reading to an app every 5 minutes. How many readings arrive in 6 hours?
20. 20.💡 A red LED uses 2 V and should get 10 mA. It runs from a 6 V supply. What resistor (in ohms) is needed in series?
21. 21.🔌 Is a paper strip a conductor or an insulator? (a) a conductor (b) an insulator
22. 22.⚡ What does an electric drill mainly change electricity into? (a) heat (b) light (c) sound (d) movement
23. 23.What does an LDR do? (a) senses how bright it is (b) smooths a wobbly supply (c) turns a fan or wheels (d) beeps for an alarm
24. 24.🧾 A family uses 170 units of electricity in a month and each unit costs ₹5. What is the bill (in ₹)?
25. 25.📏 In the water-pipe picture of a circuit, voltage is like … (a) the pipe colour (b) the water pressure (c) the water tank lid (d) the tap handle
26. 26.🔺 A current of 0.2 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
27. 27.🔍 Which is the odd one out? (a) a keypad (b) an LED (c) a temperature sensor (d) a motion sensor
28. 28.💡 2 identical bulbs are joined in series with a 5 V battery (ideal wires). How many volts does each bulb get? =
29. 29.🧮 A 47 Ω resistor is joined in series with two equal 1000 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
30. 30.⚠️ Is it safe to keep drinks far away? (a) safe (b) not safe
31. 31.True or false: to share camera links is a risky habit. (a) False (b) True
32. 32.🤖 Does a digital alarm clock usually have a microcontroller inside? (a) No (b) Yes
33. 33.Which of these means the circuit is closed? (a) the switch is OFF (b) all wires are joined (c) the bulb is unscrewed (d) a wire has come loose
34. 34.🔐 Who should decide which smart devices go in a child’s room? (a) a parent or guardian (b) the app’s adverts (c) nobody at all (d) an online stranger
35. 35.Which of these is measured in amperes (A)? (a) the push of a cell (b) resistance (c) power (d) current
36. 36.🤖 Microcontroller or laptop: which one has a built-in keyboard? (a) microcontroller (b) laptop
37. 37.Which of these is a risky habit? (a) tap unknown app links (b) log out of shared phones (c) set up with a parent (d) install software updates
38. 38.True or false: a steel coin is a conductor. (a) False (b) True
39. 39.💡 2 identical bulbs are joined in series with a battery and a closed switch on the main wire. Bulb 2 is taken out of its holder. Does bulb 1 glow? (a) Yes (b) No
40. 40.Which drawing is the symbol for a switch? (a) a line lifted at a gap (b) one tall, one short bar (c) two or more cell symbols (d) a circle with V inside

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