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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 944 · 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.🧮 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
  2. 2.🌈 Which band is read first on a resistor? (a) any band (b) the gold band (c) the one nearest an end (d) the widest gap
  3. 3.💡 An LED is joined to a 9 V battery through a 330 Ω resistor; the leg next to the flat edge of its rim goes to the + side. What happens? (a) lights up (b) does not light (c) may burn out
  4. 4.⚡ A home appliance on the 230 V mains takes 0.5 A. What is its power (in watts)?
  5. 5.🔺 A current of 40 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
  6. 6.🌈 A gold fourth band on a resistor means the value may be off by … (a) 50 % (b) 0 % (c) 25 % (d) 5 %
  7. 7.🧮 Resistors of 47 Ω and 470 Ω are joined in series. What is the total resistance (in ohms)?
  8. 8.🔺 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
  9. 9.🧮 Resistors of 22 Ω and 100 Ω are joined in series. What is the total resistance (in ohms)?
  10. 10.🌈 A resistor has the colour bands red, violet, brown. What is its value (in ohms)?
  11. 11.Which of these is measured in ohms (Ω)? (a) resistance (b) current (c) voltage (d) energy used each second
  12. 12.📏 How many kilo-ohms (kΩ) is 9200 Ω? =
  13. 13.🔺 A 20 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
  14. 14.⚡ Power tells us … (a) the length of a wire (b) energy used each second (c) the colour of light (d) the size of a cell
  15. 15.🔺 A current of 10 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
  16. 16.🔺 An 18 V supply is joined across a 12 Ω resistor. What current flows (in amperes)? =
  17. 17.🧮 A 47 Ω resistor is joined in series with two equal 10 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  18. 18.💡 A red LED (it uses 2 V) is joined with a 150 Ω resistor to a 2.75 V supply. What current flows (in mA)?
  19. 19.🔺 A current of 1.5 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
  20. 20.🧮 Two equal 100 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  21. 21.🔺 A current of 25 mA flows when 5 V is joined across a resistor. What is its resistance (in ohms)?
  22. 22.🔺 A current of 0.25 A flows when 5 V is joined across a resistor. What is its resistance (in ohms)?
  23. 23.🔺 A current of 10 mA flows when 4 V is joined across a resistor. What is its resistance (in ohms)?
  24. 24.True or false: to unplug idle chargers saves electricity. (a) False (b) True
  25. 25.🔺 A current of 0.25 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
  26. 26.True or false: current is measured in volts (V). (a) False (b) True
  27. 27.⚡ A 4.5 W device works on 3 V. What current does it take (in amperes)? =
  28. 28.Which of these is measured in volts (V)? (a) energy used each second (b) current (c) the flow of charge (d) the push of a cell
  29. 29.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  30. 30.🔺 A current of 2 A flows when 6 V is joined across a resistor. What is its resistance (in ohms)?
  31. 31.🧾 A 1500 W appliance runs for 6 hours. How many units (kWh) of electricity does it use? =
  32. 32.🧩 Which component blows if current is high? (a) capacitor (b) fuse (c) LDR (d) resistor
  33. 33.🌈 In the resistor colour code, which number does violet stand for?
  34. 34.🔍 Which is the odd one out? (a) use old filament bulbs (b) iron one shirt at a time (c) leave the TV on standby (d) use LED lamps
  35. 35.🧩 A capacitor in a circuit can … (a) make light (b) store charge briefly (c) spin a wheel (d) measure heat
  36. 36.💡 Does it save or waste electricity to use daylight to read? (a) saves electricity (b) wastes electricity
  37. 37.🔍 Which is the odd one out? (a) leave fridge door open (b) iron one shirt at a time (c) run fans in empty rooms (d) set the AC to 24 °C
  38. 38.💡 A red LED (it uses 2 V) is joined with a 150 Ω resistor to a 4.25 V supply. What current flows (in mA)?
  39. 39.💡 A blue LED uses 3 V and should get 10 mA. It runs from a 9 V supply. What resistor (in ohms) is needed in series?
  40. 40.True or false: a resistor makes a beeping sound. (a) True (b) False

Answer key

  1. less than either one
  2. the one nearest an end
  3. does not light
  4. 115
  5. 13.2
  6. 5 %
  7. 517
  8. V = I × R
  9. 122
  10. 270
  11. resistance
  12. 9.2
  13. 2
  14. energy used each second
  15. 1
  16. 1.5
  17. 52
  18. 5
  19. 3
  20. 50
  21. 200
  22. 20
  23. 400
  24. True
  25. 5
  26. False
  27. 1.5
  28. the push of a cell
  29. anode (+)
  30. 3
  31. 9
  32. fuse
  33. 7
  34. use LED lamps
  35. store charge briefly
  36. saves electricity
  37. set the AC to 24 °C
  38. 15
  39. 600
  40. False

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