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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 866 · 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 0.1 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
  2. 2.🔺 In the V-I-R triangle, how do we find I? (a) I = V ÷ R (b) I = V × R (c) I = V + R (d) I = R ÷ V
  3. 3.True or false: the voltmeter measures current. (a) False (b) True
  4. 4.🔺 In the V-I-R triangle, how do we find V? (a) V = I ÷ R (b) V = R ÷ I (c) V = I × R (d) V = I + R
  5. 5.⚡ A home appliance on the 230 V mains takes 2 A. What is its power (in watts)?
  6. 6.⚡ A device works on 3 V and takes 0.1 A. What is its power (in watts)? =
  7. 7.🌈 A gold fourth band on a resistor means the value may be off by … (a) 25 % (b) 50 % (c) 0 % (d) 5 %
  8. 8.⚡ A home appliance on the 230 V mains takes 0.5 A. What is its power (in watts)?
  9. 9.🔺 A current of 40 mA flows when 18.8 V is joined across a resistor. What is its resistance (in ohms)?
  10. 10.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 57 Ω resistor? (a) blue-violet-black (b) green-violet-black (c) violet-green-black (d) green-violet-brown
  11. 11.📏 How many kilo-ohms (kΩ) is 5100 Ω? =
  12. 12.🔺 A 12 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
  13. 13.True or false: the voltmeter measures voltage. (a) False (b) True
  14. 14.What does a fuse do? (a) has coloured bands (b) smooths a wobbly supply (c) senses how bright it is (d) blows if current is high
  15. 15.🧮 A 0.6 V battery is joined to 2 Ω and 4 Ω resistors in series. What current flows (in amperes)? =
  16. 16.💡 A red LED (it uses 2 V) is joined with a 200 Ω resistor to a 6 V supply. What current flows (in mA)?
  17. 17.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V ÷ I (c) P = V + I (d) P = V × I
  18. 18.🔺 A 0.4 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
  19. 19.🌈 A resistor has the colour bands orange, blue, red. What is its value (in ohms)?
  20. 20.⚡ A device works on 3 V and takes 0.25 A. What is its power (in watts)? =
  21. 21.⚡ A device works on 9 V and takes 0.5 A. What is its power (in watts)? =
  22. 22.🌈 In the resistor colour code, which number does violet stand for?
  23. 23.🧮 Adding another resistor in series makes the total resistance … (a) zero (b) stay the same (c) smaller (d) bigger
  24. 24.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  25. 25.🔺 A current of 1.5 A flows when 3 V is joined across a resistor. What is its resistance (in ohms)?
  26. 26.🧮 Three equal 300 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  27. 27.💡 Does it save or waste electricity to use LED lamps? (a) saves electricity (b) wastes electricity
  28. 28.🔺 A current of 50 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
  29. 29.🔺 A current of 0.1 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
  30. 30.True or false: on an LED, the round-side leg is the anode (+). (a) True (b) False
  31. 31.Which of these saves electricity? (a) use daylight to read (b) use old filament bulbs (c) leave the TV on standby (d) leave fridge door open
  32. 32.🔺 A current of 3 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
  33. 33.Which of these is measured in amperes (A)? (a) the push of a cell (b) current (c) how much a part resists (d) energy used each second
  34. 34.🧮 A 4 V battery is joined to 4 Ω and 4 Ω resistors in series. What current flows (in amperes)? =
  35. 35.🔺 A 2.5 V supply is joined across a 100 Ω resistor. What current flows (in milliamperes, mA)?
  36. 36.🧩 Which component has coloured bands? (a) thermistor (b) buzzer (c) LED (d) resistor
  37. 37.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) becomes zero (b) gets bigger (c) gets smaller (d) stays the same
  38. 38.True or false: a diode makes things spin. (a) False (b) True
  39. 39.🧩 Which component is a resistance knob? (a) potentiometer (b) transistor (c) resistor (d) motor
  40. 40.🔺 A current of 1 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =

Answer key

  1. 0.3
  2. I = V ÷ R
  3. False
  4. V = I × R
  5. 460
  6. 0.3
  7. 5 %
  8. 115
  9. 470
  10. green-violet-black
  11. 5.1
  12. 2
  13. True
  14. blows if current is high
  15. 0.1
  16. 20
  17. P = V × I
  18. 0.2
  19. 3600
  20. 0.75
  21. 4.5
  22. 7
  23. bigger
  24. cathode (−)
  25. 2
  26. 100
  27. saves electricity
  28. 20
  29. 0.4
  30. True
  31. use daylight to read
  32. 60
  33. current
  34. 0.5
  35. 25
  36. resistor
  37. gets smaller
  38. False
  39. potentiometer
  40. 6

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