Electronics Worksheet: Final Test

Electronics lesson 30: Final electronics test · Set 945 · 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 current of 2.5 A flows when 7.5 V is joined across a resistor. What is its resistance (in ohms)?
2. 2.🔗 Series or parallel circuit: “many paths for current”? (a) parallel (b) series
3. 3.⚡ A 0.5 W device works on 5 V. What current does it take (in amperes)? =
4. 4.🔍 Which is the odd one out? (a) a paper calendar (b) a wind-up clock (c) a plain table fan (d) a Wi-Fi weather station
5. 5.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
6. 6.⚡ What do we call a flow of electric charge through a wire? (a) friction (b) a magnet (c) sound (d) electric current
7. 7.🔋 What should you do with used-up cells? (a) give them for recycling (b) cut them open (c) throw them in a fire (d) bury them in soil
8. 8.🔁 total = 0
   for i = 1 to 4 { total = total + i }
   What is total at the end?
9. 9.🔦 A tester circuit has a new cell, a good bulb and wires with a gap between two clips. We put a safety pin across the gap. Does the bulb glow? (a) No (b) Yes
10. 10.True or false: a slide switch slides side to side. (a) True (b) False
11. 11.True or false: to set the AC to 24 °C saves electricity. (a) False (b) True
12. 12.💡 Old festival light strings went fully dark when one bulb failed. How were they joined? (a) not joined (b) in parallel (c) by Wi-Fi (d) in series
13. 13.True or false: “a single current path” is true of a parallel circuit. (a) False (b) True
14. 14.💡 A red LED (it uses 2 V) is joined with a 100 Ω resistor to a 3 V supply. What current flows (in mA)?
15. 15.✏️ Why do engineers draw circuits with symbols? (a) to hide the circuit (b) to make it colourful (c) symbols are heavier (d) quick and clear for all
16. 16.⚡ What does a doorbell mainly change electricity into? (a) sound (b) light (c) movement (d) heat
17. 17.🧮 Three equal 60 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
18. 18.True or false: a line lifted at a gap is the symbol for a capacitor. (a) False (b) True
19. 19.True or false: to run fans in empty rooms saves electricity. (a) True (b) False
20. 20.🔋 Does a bicycle dynamo give electricity or use electricity? (a) gives electricity (b) uses electricity
21. 21.🔢 To get a sensor reading onto a phone, which is the LAST step? (a) the board reads it (b) the cloud stores it (c) it is sent by Wi-Fi (d) the app shows it
22. 22.🌐 A weather station sends one reading every 10 seconds. How many readings does it send in 2 minutes?
23. 23.🧾 A family uses 70 units of electricity in a month and each unit costs ₹8. What is the bill (in ₹)?
24. 24.🔐 Which is the strongest password for a home smart camera? (a) 123456 (b) admin (c) password (d) Tiger#Lamp42!Moon
25. 25.🧮 Two resistors in parallel give a total that is … (a) more than either one (b) their sum (c) always zero (d) less than either one
26. 26.⏱️ loop forever { LED ON; wait 200 ms; LED OFF; wait 1000 ms }
    How many milliseconds does one blink (ON + OFF) take?
27. 27.⚠️ Is it safe to dry your hands first? (a) safe (b) not safe
28. 28.Which of these is an input? (a) a push button (b) an LED (c) a small display (d) a buzzer
29. 29.Which job needs a display? (a) beep an alarm (b) move water to plants (c) show the temperature (d) spin a robot’s wheels
30. 30.Which job needs a temperature sensor? (a) switch on lamps at dusk (b) water a dry plant (c) warn of a gas leak (d) keep an incubator warm
31. 31.🔍 Which is the odd one out? (a) a sound sensor (b) a motion sensor (c) a motor (d) a keypad
32. 32.🌈 In the resistor colour code, which number does violet stand for?
33. 33.💡 6 identical bulbs are joined in series with a battery and a closed switch on the main wire. All the bulbs are in place. Does bulb 3 glow? (a) No (b) Yes
34. 34.🔺 A 1.5 V supply is joined across a 150 Ω resistor. What current flows (in milliamperes, mA)?
35. 35.🔺 A current of 25 mA flows when 8.25 V is joined across a resistor. What is its resistance (in ohms)?
36. 36.🔍 Which is the odd one out? (a) use old filament bulbs (b) run fans in empty rooms (c) unplug idle chargers (d) leave fridge door open
37. 37.🔋 On a cell, does “the end with a bump” mean the + end or the − end? (a) + (positive) (b) − (negative)
38. 38.⚠️ Is it safe to touch a fallen wire? (a) safe (b) not safe
39. 39.True or false: on a cell, “the shorter symbol line” means the − (negative) end. (a) False (b) True
40. 40.🔘 A cell, a bulb and switches A, B, C and D are joined one after another in a single loop (series). A is OFF, B is ON, C is ON and D is ON. Does the bulb glow? (a) No (b) Yes

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