Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 581 · 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.🌈 A resistor has the colour bands red, grey, red. What is its value (in ohms)?
2. 2.🌈 A resistor has the colour bands violet, red, orange. What is its value (in ohms)?
3. 3.Which of these saves electricity? (a) run fans in empty rooms (b) set the AC to 24 °C (c) use old filament bulbs (d) iron one shirt at a time
4. 4.🧾 Which lamp gives the same light for the least power? (a) an oil lamp (b) an LED lamp (c) a candle (d) a filament bulb
5. 5.🔺 A 4 V supply is joined across a 400 Ω resistor. What current flows (in milliamperes, mA)?
6. 6.Which of these is measured in volts (V)? (a) the flow of charge (b) voltage (c) current (d) resistance
7. 7.🔍 Which is the odd one out? (a) unplug idle chargers (b) use daylight to read (c) switch off empty rooms (d) use old filament bulbs
8. 8.🧮 A 5 V battery is joined to 10 Ω and 10 Ω resistors in series. What current flows (in amperes)? =
9. 9.🔺 A current of 10 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
10. 10.🔺 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
11. 11.🌈 Which band is read first on a resistor? (a) the one nearest an end (b) the gold band (c) any band (d) the widest gap
12. 12.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 630 Ω resistor? (a) blue-orange-black (b) blue-orange-red (c) orange-blue-brown (d) blue-orange-brown
13. 13.📏 How many amperes (A) is 820 mA? =
14. 14.Which of these is measured in watts (W)? (a) voltage (b) the flow of charge (c) power (d) resistance
15. 15.🔍 Which is the odd one out? (a) use LED lamps (b) leave fridge door open (c) close the fridge quickly (d) use daylight to read
16. 16.🔺 In the V-I-R triangle, how do we find V? (a) V = I + R (b) V = I ÷ R (c) V = I × R (d) V = R ÷ I
17. 17.🔺 A current of 50 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
18. 18.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
19. 19.🧮 Resistors of 20 Ω and 22 Ω are joined in series. What is the total resistance (in ohms)?
20. 20.🔺 A 1.6 V supply is joined across an 8 Ω resistor. What current flows (in amperes)? =
21. 21.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) stays the same (b) gets bigger (c) gets smaller (d) becomes zero
22. 22.📏 How many milliamperes (mA) is 2.04 A?
23. 23.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark an 81 Ω resistor? (a) white-brown-black (b) brown-grey-black (c) grey-brown-black (d) grey-brown-brown
24. 24.🔺 A 10 V supply is joined across a 500 Ω resistor. What current flows (in milliamperes, mA)?
25. 25.🧾 A family uses 20 units of electricity in a month and each unit costs ₹5. What is the bill (in ₹)?
26. 26.🧮 Two resistors in parallel give a total that is … (a) their sum (b) always zero (c) less than either one (d) more than either one
27. 27.📏 In the water-pipe picture of a circuit, voltage is like … (a) the water pressure (b) the tap handle (c) the water tank lid (d) the pipe colour
28. 28.🧾 One “unit” on an electricity bill is … (a) 1 kilowatt-hour (kWh) (b) 1 volt (c) 1 watt (d) 1 ampere
29. 29.⚡ A device works on 6 V and takes 1.5 A. What is its power (in watts)? =
30. 30.🔺 A current of 1 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
31. 31.🧮 Two equal 330 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
32. 32.Which of these is measured in volts (V)? (a) the push of a cell (b) the flow of charge (c) current (d) energy used each second
33. 33.⚡ A home appliance on the 230 V mains takes 10 A. What is its power (in watts)?
34. 34.⚡ Power tells us … (a) the colour of light (b) the length of a wire (c) the size of a cell (d) energy used each second
35. 35.🧮 A 47 Ω resistor is joined in series with two equal 470 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
36. 36.📏 How many watts (W) is 2 kW?
37. 37.True or false: on an LED, the longer leg is the anode (+). (a) False (b) True
38. 38.🌈 In the resistor colour code, which number does blue stand for?
39. 39.🔺 A 1.2 V supply is joined across a 120 Ω resistor. What current flows (in milliamperes, mA)?
40. 40.🧮 Two equal 220 Ω resistors are joined in parallel. What is the total resistance (in ohms)?

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