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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 835 · 40 questions
TalentJR

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.

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  1. 1.🔺 A current of 40 mA flows when 8.8 V is joined across a resistor. What is its resistance (in ohms)?
  2. 2.🌈 A resistor has the colour bands green, grey, black. What is its value (in ohms)?
  3. 3.🔺 A 4 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
  4. 4.🌈 Which band is read first on a resistor? (a) any band (b) the widest gap (c) the gold band (d) the one nearest an end
  5. 5.💡 A blue LED uses 3 V and should get 10 mA. It runs from a 12 V supply. What resistor (in ohms) is needed in series?
  6. 6.🔺 A current of 0.5 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
  7. 7.What does a capacitor do? (a) senses how hot it is (b) blows if current is high (c) has coloured bands (d) smooths a wobbly supply
  8. 8.🔺 A current of 25 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
  9. 9.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) stays the same (b) gets bigger (c) becomes zero (d) gets smaller
  10. 10.🌈 In the resistor colour code, which number does black stand for?
  11. 11.⚡ A device works on 12 V and takes 0.1 A. What is its power (in watts)? =
  12. 12.⚡ A 0.15 W device works on 1.5 V. What current does it take (in amperes)? =
  13. 13.🌈 In the resistor colour code, which number does brown stand for?
  14. 14.📏 In the water-pipe picture of a circuit, voltage is like … (a) the water pressure (b) the pipe colour (c) the water tank lid (d) the tap handle
  15. 15.📏 How many kilowatts (kW) is 3150 W? =
  16. 16.🔺 A current of 0.25 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
  17. 17.🔺 A current of 3 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
  18. 18.📏 How many watts (W) is 3.7 kW?
  19. 19.🧾 A family uses 150 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
  20. 20.🌈 A gold fourth band on a resistor means the value may be off by … (a) 5 % (b) 0 % (c) 25 % (d) 50 %
  21. 21.What does a fuse do? (a) smooths a wobbly supply (b) blows if current is high (c) limits the current (d) makes things spin
  22. 22.🔺 A current of 25 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
  23. 23.🧩 Which component blows if current is high? (a) resistor (b) transistor (c) motor (d) fuse
  24. 24.⚡ A home appliance on the 230 V mains takes 4 A. What is its power (in watts)?
  25. 25.🔺 A current of 2 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
  26. 26.🔺 A current of 40 mA flows when 4 V is joined across a resistor. What is its resistance (in ohms)?
  27. 27.🌈 A resistor has the colour bands blue, black, red. What is its value in kilo-ohms (kΩ)? =
  28. 28.🌈 In the resistor colour code, which number does violet stand for?
  29. 29.⚡ A device works on 12 V and takes 0.25 A. What is its power (in watts)? =
  30. 30.🧮 Two resistors in parallel give a total that is … (a) always zero (b) their sum (c) less than either one (d) more than either one
  31. 31.True or false: the push of a cell is measured in volts (V). (a) True (b) False
  32. 32.🔺 A current of 10 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
  33. 33.🔺 A current of 1.5 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
  34. 34.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 2600 Ω resistor? (a) blue-red-red (b) red-blue-orange (c) red-blue-brown (d) red-blue-red
  35. 35.True or false: a buzzer smooths a wobbly supply. (a) True (b) False
  36. 36.🔺 A current of 1.5 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
  37. 37.🧩 A capacitor in a circuit can … (a) store charge briefly (b) measure heat (c) spin a wheel (d) make light
  38. 38.📏 In the water-pipe picture of a circuit, current is like … (a) the water pressure (b) the pipe colour (c) the flow of water (d) a narrow pipe
  39. 39.🧾 A 500 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
  40. 40.🔺 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

Answer key

  1. 220
  2. 58
  3. 0.2
  4. the one nearest an end
  5. 900
  6. 1
  7. smooths a wobbly supply
  8. 2.5
  9. gets smaller
  10. 0
  11. 1.2
  12. 0.1
  13. 1
  14. the water pressure
  15. 3.15
  16. 1.5
  17. 24
  18. 3700
  19. 1350
  20. 5 %
  21. blows if current is high
  22. 3.75
  23. fuse
  24. 920
  25. 40
  26. 100
  27. 6
  28. 7
  29. 3
  30. less than either one
  31. True
  32. 4
  33. 4.5
  34. red-blue-red
  35. False
  36. 18
  37. store charge briefly
  38. the flow of water
  39. 5
  40. V = I × R

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