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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 19 · 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 home appliance on the 230 V mains takes 4 A. What is its power (in watts)?
  2. 2.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark an 8300 Ω resistor? (a) grey-orange-orange (b) orange-grey-red (c) grey-orange-brown (d) grey-orange-red
  3. 3.🔺 A 23.5 V supply is joined across a 470 Ω resistor. What current flows (in milliamperes, mA)?
  4. 4.Which of these is measured in volts (V)? (a) how much a part resists (b) voltage (c) resistance (d) the flow of charge
  5. 5.True or false: on an LED, the leg by the flat edge is the anode (+). (a) False (b) True
  6. 6.🧩 Which component is a resistance knob? (a) buzzer (b) resistor (c) fuse (d) potentiometer
  7. 7.🌈 A resistor has the colour bands grey, black, orange. What is its value in kilo-ohms (kΩ)? =
  8. 8.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 9 hours. How many watt-hours (Wh) are saved?
  9. 9.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 6000 Ω resistor? (a) violet-blue-red (b) blue-black-red (c) blue-black-orange (d) blue-black-brown
  10. 10.🌈 A resistor has the colour bands blue, brown, orange. What is its value (in ohms)?
  11. 11.💡 An LED is joined to a 3 V battery through a 1000 Ω resistor; its long leg goes to the + side and its short leg to the − side. What happens? (a) does not light (b) lights up (c) may burn out
  12. 12.⚡ A 0.375 W device works on 1.5 V. What current does it take (in amperes)? =
  13. 13.🌈 A resistor has the colour bands blue, yellow, red. What is its value (in ohms)?
  14. 14.🔺 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
  15. 15.📏 Voltmeter or ammeter: which one is joined in series? (a) ammeter (b) voltmeter
  16. 16.🔺 A current of 3 A flows when 9 V is joined across a resistor. What is its resistance (in ohms)?
  17. 17.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 210 Ω resistor? (a) red-brown-brown (b) red-brown-black (c) brown-red-brown (d) red-brown-red
  18. 18.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  19. 19.💡 An LED is joined to a 3 V battery through a 470 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
  20. 20.⚡ Which formula gives electric power? (a) P = V + I (b) P = V ÷ I (c) P = I ÷ V (d) P = V × I
  21. 21.🔺 A 9 V supply is joined across a 3 Ω resistor. What current flows (in amperes)? =
  22. 22.💡 Does it save or waste electricity to use old filament bulbs? (a) wastes electricity (b) saves electricity
  23. 23.True or false: to unplug idle chargers wastes electricity. (a) False (b) True
  24. 24.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets smaller (b) gets bigger (c) stays the same (d) becomes zero
  25. 25.🌈 A resistor has the colour bands white, blue, orange. What is its value (in ohms)?
  26. 26.🔺 A current of 10 mA flows when 4 V is joined across a resistor. What is its resistance (in ohms)?
  27. 27.Which of these wastes electricity? (a) iron one shirt at a time (b) use LED lamps (c) close the fridge quickly (d) switch off empty rooms
  28. 28.🧾 One “unit” on an electricity bill is … (a) 1 kilowatt-hour (kWh) (b) 1 ampere (c) 1 watt (d) 1 volt
  29. 29.🧾 A 1000 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
  30. 30.What does an LDR do? (a) glows using little power (b) makes a beeping sound (c) turns a fan or wheels (d) senses how bright it is
  31. 31.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 6 hours. How many watt-hours (Wh) are saved?
  32. 32.🧾 A 100 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
  33. 33.⚡ A device works on 3 V and takes 0.25 A. What is its power (in watts)? =
  34. 34.🧮 Two resistors in parallel give a total that is … (a) less than either one (b) their sum (c) always zero (d) more than either one
  35. 35.Which of these is measured in ohms (Ω)? (a) voltage (b) power (c) energy used each second (d) how much a part resists
  36. 36.True or false: a motor makes things spin. (a) True (b) False
  37. 37.True or false: a capacitor stores a little charge. (a) False (b) True
  38. 38.📏 Voltmeter or ammeter: which one is joined across a part? (a) ammeter (b) voltmeter
  39. 39.🌈 A resistor has the colour bands grey, grey, orange. What is its value (in ohms)?
  40. 40.🔺 A current of 2 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =

Answer key

  1. 920
  2. grey-orange-red
  3. 50
  4. voltage
  5. False
  6. potentiometer
  7. 80
  8. 459
  9. blue-black-red
  10. 61000
  11. lights up
  12. 0.25
  13. 6400
  14. V = I × R
  15. ammeter
  16. 3
  17. red-brown-brown
  18. anode (+)
  19. does not light
  20. P = V × I
  21. 3
  22. wastes electricity
  23. False
  24. gets smaller
  25. 96000
  26. 400
  27. iron one shirt at a time
  28. 1 kilowatt-hour (kWh)
  29. 2
  30. senses how bright it is
  31. 306
  32. 0.2
  33. 0.75
  34. less than either one
  35. how much a part resists
  36. True
  37. True
  38. voltmeter
  39. 88000
  40. 20

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