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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 176 · 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 = I ÷ V (c) P = V ÷ I (d) P = V × I
  2. 2.True or false: a motor turns a fan or wheels. (a) True (b) False
  3. 3.🔺 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
  4. 4.🧮 A 4 V battery is joined to 2 Ω and 2 Ω resistors in series. What current flows (in amperes)? =
  5. 5.📏 Which unit measures the flow of charge? (a) volt (V) (b) watt (W) (c) ampere (A) (d) ohm (Ω)
  6. 6.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  7. 7.⚡ A home appliance on the 230 V mains takes 4 A. What is its power (in watts)?
  8. 8.What does a potentiometer do? (a) makes a beeping sound (b) lets current go one way (c) is a resistance knob (d) senses how hot it is
  9. 9.🔺 A current of 10 mA flows through a 250 Ω resistor. What is the voltage across it (in volts)? =
  10. 10.🌈 A resistor has the colour bands orange, brown, brown. What is its value (in ohms)?
  11. 11.🔺 A 3 V supply is joined across a 150 Ω resistor. What current flows (in milliamperes, mA)?
  12. 12.Which of these is measured in ohms (Ω)? (a) voltage (b) the flow of charge (c) how much a part resists (d) current
  13. 13.True or false: a resistor limits the current. (a) True (b) False
  14. 14.📏 In the water-pipe picture of a circuit, current is like … (a) the pipe colour (b) a narrow pipe (c) the flow of water (d) the water pressure
  15. 15.🔺 A 16 V supply is joined across a 400 Ω resistor. What current flows (in milliamperes, mA)?
  16. 16.True or false: on an LED, the shorter leg is the anode (+). (a) True (b) False
  17. 17.🔺 A 1.2 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
  18. 18.🔺 A current of 50 mA flows when 23.5 V is joined across a resistor. What is its resistance (in ohms)?
  19. 19.⚡ A 2.25 W device works on 9 V. What current does it take (in amperes)? =
  20. 20.🌈 A resistor has the colour bands blue, black, red. What is its value (in ohms)?
  21. 21.📏 How many ohms make 1 kilo-ohm (kΩ)? (a) 1000 (b) 10 (c) 1024 (d) 100
  22. 22.🔺 A current of 0.5 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
  23. 23.⚡ Power tells us … (a) the colour of light (b) the length of a wire (c) energy used each second (d) the size of a cell
  24. 24.True or false: on an LED, the leg by the flat edge is the cathode (−). (a) True (b) False
  25. 25.📏 Voltmeter or ammeter: which one measures voltage? (a) ammeter (b) voltmeter
  26. 26.🔺 A current of 2.5 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
  27. 27.Which of these is measured in volts (V)? (a) current (b) power (c) voltage (d) the flow of charge
  28. 28.True or false: the voltmeter is joined across a part. (a) False (b) True
  29. 29.🧮 Resistors of 68 Ω and 20 Ω are joined in series. What is the total resistance (in ohms)?
  30. 30.🧩 Which component senses how bright it is? (a) buzzer (b) motor (c) LDR (d) fuse
  31. 31.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets bigger (b) gets smaller (c) becomes zero (d) stays the same
  32. 32.🔺 A current of 0.1 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
  33. 33.🧩 Which part changes electrical energy into movement? (a) an LED (b) a fuse (c) a resistor (d) a motor
  34. 34.🧩 Which component makes things spin? (a) LED (b) motor (c) capacitor (d) resistor
  35. 35.🧮 A 1.75 V battery is joined to 4 Ω and 3 Ω resistors in series. What current flows (in amperes)? =
  36. 36.🔺 A current of 1 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
  37. 37.True or false: the push of a cell is measured in amperes (A). (a) True (b) False
  38. 38.🧾 A 50 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
  39. 39.Which of these is measured in watts (W)? (a) voltage (b) energy used each second (c) how much a part resists (d) the flow of charge
  40. 40.🧮 Resistors of 10 Ω and 10 Ω are joined in series. What is the total resistance (in ohms)?

Answer key

  1. P = V × I
  2. True
  3. V = I × R
  4. 1
  5. ampere (A)
  6. cathode (−)
  7. 920
  8. is a resistance knob
  9. 2.5
  10. 310
  11. 20
  12. how much a part resists
  13. True
  14. the flow of water
  15. 40
  16. False
  17. 0.2
  18. 470
  19. 0.25
  20. 6000
  21. 1000
  22. 3
  23. energy used each second
  24. True
  25. voltmeter
  26. 5
  27. voltage
  28. True
  29. 88
  30. LDR
  31. gets smaller
  32. 0.8
  33. a motor
  34. motor
  35. 0.25
  36. 6
  37. False
  38. 0.1
  39. energy used each second
  40. 20

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