Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 371 · 40 questions

Remember (Find the topic, use the formula): Find the topic and the formula: V = I × R, I = V ÷ R, R = V ÷ I, P = V × I, units = W × h ÷ 1000. Change mA to A and kΩ to Ω before using a formula. Check: put your answer back into the formula.

1. 1.🔺 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
2. 2.Which of these saves electricity? (a) use old filament bulbs (b) iron one shirt at a time (c) unplug idle chargers (d) leave fridge door open
3. 3.🌈 A gold fourth band on a resistor means the value may be off by … (a) 25 % (b) 50 % (c) 5 % (d) 0 %
4. 4.💡 What does LED stand for? (a) light-emitting diode (b) low energy device (c) light energy dial (d) large electric dial
5. 5.📏 Voltmeter or ammeter: which one measures voltage? (a) voltmeter (b) ammeter
6. 6.📏 How many kilowatts (kW) is 4600 W? =
7. 7.🌈 A resistor has the colour bands white, blue, orange. What is its value (in ohms)?
8. 8.🌈 A resistor has the colour bands yellow, yellow, red. What is its value in kilo-ohms (kΩ)? =
9. 9.What does a resistor do? (a) boosts a small signal (b) is a resistance knob (c) limits the current (d) senses how hot it is
10. 10.🔺 A current of 0.5 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
11. 11.🧮 Two equal 20 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
12. 12.💡 A red LED (it uses 2 V) is joined with a 200 Ω resistor to a 5 V supply. What current flows (in mA)?
13. 13.🧾 A family uses 40 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
14. 14.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 33 Ω resistor? (a) orange-orange-brown (b) yellow-orange-black (c) orange-orange-black (d) orange-yellow-black
15. 15.True or false: a motor makes a beeping sound. (a) True (b) False
16. 16.🌈 In the resistor colour code, which number does black stand for?
17. 17.🧩 Which part changes electrical energy into sound? (a) a buzzer (b) a capacitor (c) a resistor (d) a diode
18. 18.⚡ A device works on 6 V and takes 3 A. What is its power (in watts)? =
19. 19.True or false: to close the fridge quickly saves electricity. (a) False (b) True
20. 20.🔺 A current of 20 mA flows when 4 V is joined across a resistor. What is its resistance (in ohms)?
21. 21.🔺 A current of 0.5 A flows when 2.5 V is joined across a resistor. What is its resistance (in ohms)?
22. 22.📏 How many ohms (Ω) is 2.9 kΩ?
23. 23.💡 Does it save or waste electricity to iron one shirt at a time? (a) saves electricity (b) wastes electricity
24. 24.🔺 In the V-I-R triangle, how do we find I? (a) I = V ÷ R (b) I = V + R (c) I = R ÷ V (d) I = V × R
25. 25.🔺 A 6 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
26. 26.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
27. 27.💡 Why does an LED need a resistor in series? (a) to store charge (b) to limit the current (c) to change its colour (d) to make it brighter
28. 28.True or false: on an LED, the longer leg is the anode (+). (a) False (b) True
29. 29.🔺 A 4.4 V supply is joined across a 220 Ω resistor. What current flows (in milliamperes, mA)?
30. 30.🌈 In the resistor colour code, which number does orange stand for?
31. 31.📏 Voltmeter or ammeter: which one is joined in series? (a) ammeter (b) voltmeter
32. 32.⚡ A 72 W device works on 24 V. What current does it take (in amperes)? =
33. 33.💡 Does it save or waste electricity to switch off empty rooms? (a) wastes electricity (b) saves electricity
34. 34.🔺 A 0.8 V supply is joined across an 8 Ω resistor. What current flows (in amperes)? =
35. 35.🔺 A current of 40 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
36. 36.🔺 A current of 20 mA flows through a 300 Ω resistor. What is the voltage across it (in volts)? =
37. 37.Which of these wastes electricity? (a) close the fridge quickly (b) use old filament bulbs (c) switch off empty rooms (d) use LED lamps
38. 38.🧾 A 200 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =
39. 39.🌈 A resistor has the colour bands green, red, orange. What is its value in kilo-ohms (kΩ)? =
40. 40.📏 Which unit measures how much a part resists? (a) ohm (Ω) (b) ampere (A) (c) volt (V) (d) watt (W)

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