Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 989 · 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.🔍 Which is the odd one out? (a) use old filament bulbs (b) switch off empty rooms (c) use LED lamps (d) set the AC to 24 °C
2. 2.🌈 A resistor has the colour bands violet, orange, orange. What is its value in kilo-ohms (kΩ)? =
3. 3.🧩 Which part changes electrical energy into movement? (a) an LED (b) a fuse (c) a resistor (d) a motor
4. 4.True or false: a buzzer beeps for an alarm. (a) True (b) False
5. 5.🔺 In the V-I-R triangle, how do we find V? (a) V = I + R (b) V = I × R (c) V = R ÷ I (d) V = I ÷ R
6. 6.What does a diode do? (a) has coloured bands (b) blows if current is high (c) lets current go one way (d) makes a beeping sound
7. 7.⚡ A device works on 24 V and takes 0.1 A. What is its power (in watts)? =
8. 8.True or false: a buzzer smooths a wobbly supply. (a) True (b) False
9. 9.🧮 A 2.8 V battery is joined to 10 Ω and 4 Ω resistors in series. What current flows (in amperes)? =
10. 10.⚡ Power tells us … (a) the colour of light (b) the size of a cell (c) energy used each second (d) the length of a wire
11. 11.🔺 A 5 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
12. 12.💡 A red LED (it uses 2 V) is joined with a 100 Ω resistor to a 2.5 V supply. What current flows (in mA)?
13. 13.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V + I (c) P = V ÷ I (d) P = V × I
14. 14.🔺 A current of 1.5 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
15. 15.🔺 In the V-I-R triangle, how do we find I? (a) I = R ÷ V (b) I = V × R (c) I = V ÷ R (d) I = V + R
16. 16.📏 Which unit measures how much a part resists? (a) ampere (A) (b) volt (V) (c) ohm (Ω) (d) watt (W)
17. 17.🌈 A resistor has the colour bands violet, brown, orange. What is its value (in ohms)?
18. 18.📏 In the water-pipe picture of a circuit, resistance is like … (a) a narrow pipe (b) the water pressure (c) the flow of water (d) a bigger tank
19. 19.Which of these is measured in ohms (Ω)? (a) current (b) power (c) energy used each second (d) how much a part resists
20. 20.True or false: to use LED lamps wastes electricity. (a) True (b) False
21. 21.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
22. 22.🌈 A resistor has the colour bands yellow, yellow, orange. What is its value (in ohms)?
23. 23.🔺 A current of 50 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
24. 24.💡 Does it save or waste electricity to unplug idle chargers? (a) wastes electricity (b) saves electricity
25. 25.Which of these is measured in watts (W)? (a) the push of a cell (b) energy used each second (c) resistance (d) voltage
26. 26.🔺 A 20 V supply is joined across a 500 Ω resistor. What current flows (in milliamperes, mA)?
27. 27.🧾 A family uses 80 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
28. 28.🔺 A current of 50 mA flows when 11 V is joined across a resistor. What is its resistance (in ohms)?
29. 29.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
30. 30.Which of these is measured in watts (W)? (a) current (b) power (c) how much a part resists (d) voltage
31. 31.🧮 Adding another resistor in series makes the total resistance … (a) bigger (b) smaller (c) stay the same (d) zero
32. 32.🌈 A resistor has the colour bands blue, white, red. What is its value in kilo-ohms (kΩ)? =
33. 33.⚡ A 36 W device works on 24 V. What current does it take (in amperes)? =
34. 34.📏 Which unit measures power? (a) ohm (Ω) (b) volt (V) (c) watt (W) (d) ampere (A)
35. 35.🧮 Four equal 200 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
36. 36.🌈 A resistor has the colour bands yellow, red, red. What is its value (in ohms)?
37. 37.True or false: a diode lets current go one way. (a) True (b) False
38. 38.🔺 A current of 2 A flows when 24 V is joined across a resistor. What is its resistance (in ohms)?
39. 39.🌈 Which band is read first on a resistor? (a) the widest gap (b) any band (c) the gold band (d) the one nearest an end
40. 40.Which of these wastes electricity? (a) unplug idle chargers (b) set the AC to 24 °C (c) use daylight to read (d) use old filament bulbs

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