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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 539 · 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.⚡ Which formula gives electric power? (a) P = V + I (b) P = V × I (c) P = I ÷ V (d) P = V ÷ I
  2. 2.🧮 Two resistors in parallel give a total that is … (a) less than either one (b) more than either one (c) their sum (d) always zero
  3. 3.🧮 Adding another resistor in series makes the total resistance … (a) smaller (b) zero (c) bigger (d) stay the same
  4. 4.⚡ A home appliance on the 230 V mains takes 5 A. What is its power (in watts)?
  5. 5.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark an 85 Ω resistor? (a) green-grey-black (b) grey-green-brown (c) white-green-black (d) grey-green-black
  6. 6.🔺 A current of 3 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
  7. 7.🔺 An 8.8 V supply is joined across a 220 Ω resistor. What current flows (in milliamperes, mA)?
  8. 8.🔍 Which is the odd one out? (a) use daylight to read (b) unplug idle chargers (c) switch off empty rooms (d) iron one shirt at a time
  9. 9.🔺 A current of 0.2 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
  10. 10.📏 Which unit measures resistance? (a) watt (W) (b) ampere (A) (c) ohm (Ω) (d) volt (V)
  11. 11.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 520 Ω resistor? (a) red-green-brown (b) green-red-black (c) green-red-brown (d) green-red-red
  12. 12.🔺 A current of 0.1 A flows when 0.6 V is joined across a resistor. What is its resistance (in ohms)?
  13. 13.🧮 A 13 V battery is joined to 5 Ω and 8 Ω resistors in series. What current flows (in amperes)? =
  14. 14.🌈 A resistor has the colour bands green, green, black. What is its value (in ohms)?
  15. 15.🧩 Which component makes things spin? (a) potentiometer (b) diode (c) motor (d) capacitor
  16. 16.🧮 Two equal 220 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  17. 17.True or false: on an LED, the leg by the flat edge is the anode (+). (a) False (b) True
  18. 18.Which of these saves electricity? (a) leave the TV on standby (b) use old filament bulbs (c) close the fridge quickly (d) iron one shirt at a time
  19. 19.🔺 A current of 10 mA flows through a 300 Ω resistor. What is the voltage across it (in volts)? =
  20. 20.🔺 A current of 0.25 A flows when 3.75 V is joined across a resistor. What is its resistance (in ohms)?
  21. 21.True or false: a transistor has coloured bands. (a) True (b) False
  22. 22.🔺 In the V-I-R triangle, how do we find V? (a) V = I × R (b) V = I + R (c) V = R ÷ I (d) V = I ÷ R
  23. 23.📏 Voltmeter or ammeter: which one measures current? (a) voltmeter (b) ammeter
  24. 24.🔺 A current of 3 A flows when 9 V is joined across a resistor. What is its resistance (in ohms)?
  25. 25.🧩 Which part changes electrical energy into sound? (a) a capacitor (b) a buzzer (c) a diode (d) a resistor
  26. 26.🔺 A current of 0.1 A flows when 1.2 V is joined across a resistor. What is its resistance (in ohms)?
  27. 27.🔺 A current of 0.2 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
  28. 28.True or false: how much a part resists is measured in watts (W). (a) False (b) True
  29. 29.🌈 In the resistor colour code, which number does black stand for?
  30. 30.True or false: a resistor limits the current. (a) True (b) False
  31. 31.🔍 Which is the odd one out? (a) switch off empty rooms (b) use old filament bulbs (c) leave the TV on standby (d) iron one shirt at a time
  32. 32.📏 How many kilo-ohms (kΩ) is 4900 Ω? =
  33. 33.🌈 A gold fourth band on a resistor means the value may be off by … (a) 25 % (b) 50 % (c) 5 % (d) 0 %
  34. 34.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 52 Ω resistor? (a) blue-red-black (b) red-green-black (c) green-red-brown (d) green-red-black
  35. 35.🔺 A current of 3 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
  36. 36.⚡ A 0.75 W device works on 1.5 V. What current does it take (in amperes)? =
  37. 37.Which of these is measured in watts (W)? (a) the push of a cell (b) current (c) energy used each second (d) how much a part resists
  38. 38.🧮 Resistors of 20 Ω, 33 Ω and 10 Ω are joined in series. What is the total resistance (in ohms)?
  39. 39.💡 An LED is joined to a 5 V battery through a 220 Ω resistor; its long leg goes to the − side and its short leg to the + side. What happens? (a) lights up (b) may burn out (c) does not light
  40. 40.🔺 A current of 2 A flows when 24 V is joined across a resistor. What is its resistance (in ohms)?

Answer key

  1. P = V × I
  2. less than either one
  3. bigger
  4. 1150
  5. grey-green-black
  6. 45
  7. 40
  8. iron one shirt at a time
  9. 0.4
  10. ohm (Ω)
  11. green-red-brown
  12. 6
  13. 1
  14. 55
  15. motor
  16. 110
  17. False
  18. close the fridge quickly
  19. 3
  20. 15
  21. False
  22. V = I × R
  23. ammeter
  24. 3
  25. a buzzer
  26. 12
  27. 0.6
  28. False
  29. 0
  30. True
  31. switch off empty rooms
  32. 4.9
  33. 5 %
  34. green-red-black
  35. 9
  36. 0.5
  37. energy used each second
  38. 63
  39. does not light
  40. 12

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