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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 289 · 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 resistor has the colour bands grey, black, red. What is its value (in ohms)?
  2. 2.📏 Voltmeter or ammeter: which one is joined in series? (a) voltmeter (b) ammeter
  3. 3.⚡ A device works on 9 V and takes 0.2 A. What is its power (in watts)? =
  4. 4.🧩 Which component boosts a small signal? (a) potentiometer (b) diode (c) LED (d) transistor
  5. 5.True or false: on an LED, the longer leg is the anode (+). (a) True (b) False
  6. 6.True or false: the push of a cell is measured in volts (V). (a) False (b) True
  7. 7.💡 A red LED uses 2 V and should get 10 mA. It runs from a 9 V supply. What resistor (in ohms) is needed in series?
  8. 8.📏 Which unit measures power? (a) ampere (A) (b) ohm (Ω) (c) watt (W) (d) volt (V)
  9. 9.⚡ A home appliance on the 230 V mains takes 1.5 A. What is its power (in watts)?
  10. 10.🌈 In the resistor colour code, which number does brown stand for?
  11. 11.Which of these saves electricity? (a) iron one shirt at a time (b) unplug idle chargers (c) leave the TV on standby (d) run fans in empty rooms
  12. 12.📏 How many ohms make 1 kilo-ohm (kΩ)? (a) 100 (b) 10 (c) 1000 (d) 1024
  13. 13.🔺 A 4 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
  14. 14.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  15. 15.🧩 Which component glows using little power? (a) fuse (b) potentiometer (c) LED (d) diode
  16. 16.🔺 A 2.5 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =
  17. 17.🔺 A current of 40 mA flows when 4.8 V is joined across a resistor. What is its resistance (in ohms)?
  18. 18.📏 In the water-pipe picture of a circuit, current is like … (a) the pipe colour (b) the water pressure (c) the flow of water (d) a narrow pipe
  19. 19.True or false: a buzzer makes a beeping sound. (a) True (b) False
  20. 20.🔺 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
  21. 21.🧮 Two resistors in parallel give a total that is … (a) more than either one (b) always zero (c) less than either one (d) their sum
  22. 22.⚡ Power tells us … (a) the colour of light (b) energy used each second (c) the length of a wire (d) the size of a cell
  23. 23.🧩 Which component makes things spin? (a) motor (b) diode (c) transistor (d) LED
  24. 24.Which of these is measured in volts (V)? (a) resistance (b) voltage (c) how much a part resists (d) power
  25. 25.🧮 Two equal 100 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  26. 26.🌈 In the resistor colour code, which number does green stand for?
  27. 27.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  28. 28.🧾 A 1500 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
  29. 29.⚡ A home appliance on the 230 V mains takes 10 A. What is its power (in watts)?
  30. 30.📏 Voltmeter or ammeter: which one measures voltage? (a) ammeter (b) voltmeter
  31. 31.📏 Voltmeter or ammeter: which one is joined across a part? (a) ammeter (b) voltmeter
  32. 32.🧩 Which part changes electrical energy into movement? (a) an LED (b) a fuse (c) a resistor (d) a motor
  33. 33.🌈 In the resistor colour code, which number does white stand for?
  34. 34.🧮 A 15 V battery is joined to 5 Ω and 10 Ω resistors in series. What current flows (in amperes)? =
  35. 35.True or false: a capacitor smooths a wobbly supply. (a) True (b) False
  36. 36.🔺 A current of 2 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
  37. 37.⚡ Which formula gives electric power? (a) P = V × I (b) P = I ÷ V (c) P = V + I (d) P = V ÷ I
  38. 38.🌈 A resistor has the colour bands blue, brown, red. What is its value in kilo-ohms (kΩ)? =
  39. 39.🧮 Adding another resistor in series makes the total resistance … (a) smaller (b) stay the same (c) bigger (d) zero
  40. 40.What does a transistor do? (a) glows using little power (b) stores a little charge (c) beeps for an alarm (d) boosts a small signal

Answer key

  1. 8000
  2. ammeter
  3. 1.8
  4. transistor
  5. True
  6. True
  7. 700
  8. watt (W)
  9. 345
  10. 1
  11. unplug idle chargers
  12. 1000
  13. 1
  14. anode (+)
  15. LED
  16. 0.5
  17. 120
  18. the flow of water
  19. True
  20. V = I × R
  21. less than either one
  22. energy used each second
  23. motor
  24. voltage
  25. 50
  26. 5
  27. cathode (−)
  28. 15
  29. 2300
  30. voltmeter
  31. voltmeter
  32. a motor
  33. 9
  34. 1
  35. True
  36. 16
  37. P = V × I
  38. 6.1
  39. bigger
  40. boosts a small signal

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