Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 864 · 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.🔺 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
3. 3.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 1400 Ω resistor? (a) brown-yellow-orange (b) brown-yellow-brown (c) yellow-brown-red (d) brown-yellow-red
4. 4.🔺 A current of 0.5 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
5. 5.True or false: voltage is measured in ohms (Ω). (a) True (b) False
6. 6.🔺 In the V-I-R triangle, how do we find R? (a) R = I ÷ V (b) R = V + I (c) R = V × I (d) R = V ÷ I
7. 7.Which of these saves electricity? (a) run fans in empty rooms (b) switch off empty rooms (c) iron one shirt at a time (d) leave fridge door open
8. 8.Which of these wastes electricity? (a) switch off empty rooms (b) set the AC to 24 °C (c) iron one shirt at a time (d) unplug idle chargers
9. 9.🔺 A current of 10 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
10. 10.Which of these is measured in volts (V)? (a) power (b) the push of a cell (c) how much a part resists (d) the flow of charge
11. 11.⚡ Which formula gives electric power? (a) P = V + I (b) P = V ÷ I (c) P = I ÷ V (d) P = V × I
12. 12.🧾 A family uses 130 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?
13. 13.🧩 Which part changes electrical energy into sound? (a) a diode (b) a resistor (c) a buzzer (d) a capacitor
14. 14.🔺 A current of 10 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
15. 15.🧮 A 4 V battery is joined to 6 Ω and 2 Ω resistors in series. What current flows (in amperes)? =
16. 16.🌈 A resistor has the colour bands blue, brown, yellow. What is its value in kilo-ohms (kΩ)? =
17. 17.🌈 Which band is read first on a resistor? (a) the widest gap (b) the one nearest an end (c) the gold band (d) any band
18. 18.⚡ A home appliance on the 230 V mains takes 2 A. What is its power (in watts)?
19. 19.🔺 A 1 V supply is joined across a 100 Ω resistor. What current flows (in milliamperes, mA)?
20. 20.🧮 A 68 Ω resistor is joined in series with two equal 40 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
21. 21.⚡ A device works on 5 V and takes 2 A. What is its power (in watts)? =
22. 22.📏 Which unit measures the flow of charge? (a) watt (W) (b) ohm (Ω) (c) volt (V) (d) ampere (A)
23. 23.⚡ A home appliance on the 230 V mains takes 10 A. What is its power (in watts)?
24. 24.🧮 Adding another resistor in series makes the total resistance … (a) bigger (b) smaller (c) stay the same (d) zero
25. 25.True or false: on an LED, the longer leg is the cathode (−). (a) True (b) False
26. 26.🔺 A current of 1 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
27. 27.🧮 Resistors of 220 Ω, 47 Ω, 100 Ω and 10 Ω are joined in series. What is the total resistance (in ohms)?
28. 28.🔺 A current of 1 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
29. 29.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 21 Ω resistor? (a) red-brown-black (b) orange-brown-black (c) brown-red-black (d) red-brown-brown
30. 30.🔺 A 3 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
31. 31.🌈 A resistor has the colour bands grey, brown, brown. What is its value (in ohms)?
32. 32.🧮 Resistors of 10 Ω, 20 Ω and 150 Ω are joined in series. What is the total resistance (in ohms)?
33. 33.True or false: the ammeter measures voltage. (a) True (b) False
34. 34.🧮 Four equal 20 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
35. 35.💡 What happens if an LED is put in backwards? (a) it lights brighter (b) it changes colour (c) it does not light (d) it makes a sound
36. 36.⚡ A home appliance on the 230 V mains takes 1 A. What is its power (in watts)?
37. 37.🔺 A 2.4 V supply is joined across a 120 Ω resistor. What current flows (in milliamperes, mA)?
38. 38.🧾 A family uses 130 units of electricity in a month and each unit costs ₹8. What is the bill (in ₹)?
39. 39.⚡ A device works on 5 V and takes 0.2 A. What is its power (in watts)? =
40. 40.📏 How many milliamperes (mA) is 1.87 A?

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