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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 158 · 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.🔺 An 8 V supply is joined across a 200 Ω resistor. What current flows (in milliamperes, mA)?
  2. 2.🌈 A resistor has the colour bands green, black, brown. What is its value (in ohms)?
  3. 3.🧮 Three equal 150 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  4. 4.🔺 A current of 0.5 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
  5. 5.⚡ A home appliance on the 230 V mains takes 5 A. What is its power (in watts)?
  6. 6.🧮 Three equal 15 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  7. 7.🧩 Which part changes electrical energy into sound? (a) a resistor (b) a buzzer (c) a capacitor (d) a diode
  8. 8.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  9. 9.💡 Does it save or waste electricity to use daylight to read? (a) saves electricity (b) wastes electricity
  10. 10.🧩 A capacitor in a circuit can … (a) measure heat (b) spin a wheel (c) store charge briefly (d) make light
  11. 11.🧮 Resistors of 68 Ω and 150 Ω are joined in series. What is the total resistance (in ohms)?
  12. 12.⚡ A device works on 1.5 V and takes 3 A. What is its power (in watts)? =
  13. 13.💡 Does it save or waste electricity to run fans in empty rooms? (a) saves electricity (b) wastes electricity
  14. 14.🔺 A 2 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
  15. 15.🧾 A family uses 60 units of electricity in a month and each unit costs ₹5. What is the bill (in ₹)?
  16. 16.Which of these is measured in volts (V)? (a) the push of a cell (b) energy used each second (c) current (d) resistance
  17. 17.📏 Which unit measures power? (a) ohm (Ω) (b) volt (V) (c) ampere (A) (d) watt (W)
  18. 18.🔺 A current of 2 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
  19. 19.🧩 Which part changes electrical energy into movement? (a) a resistor (b) an LED (c) a fuse (d) a motor
  20. 20.True or false: on an LED, the longer leg is the anode (+). (a) True (b) False
  21. 21.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  22. 22.💡 What does LED stand for? (a) large electric dial (b) low energy device (c) light energy dial (d) light-emitting diode
  23. 23.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 2200 Ω resistor? (a) red-orange-red (b) red-red-red (c) red-red-brown (d) red-red-orange
  24. 24.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 22 Ω resistor? (a) red-red-black (b) red-red-brown (c) red-orange-black (d) orange-red-black
  25. 25.What does a diode do? (a) glows using little power (b) makes a beeping sound (c) lets current go one way (d) has coloured bands
  26. 26.🔍 Which is the odd one out? (a) leave fridge door open (b) use old filament bulbs (c) close the fridge quickly (d) run fans in empty rooms
  27. 27.🔺 In the V-I-R triangle, how do we find R? (a) R = V + I (b) R = V ÷ I (c) R = I ÷ V (d) R = V × I
  28. 28.🧾 A 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 6 hours. How many watt-hours (Wh) are saved?
  29. 29.🧩 Which component beeps for an alarm? (a) buzzer (b) capacitor (c) motor (d) diode
  30. 30.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 750 Ω resistor? (a) violet-green-red (b) green-violet-brown (c) violet-green-black (d) violet-green-brown
  31. 31.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 470 Ω resistor? (a) yellow-violet-black (b) yellow-violet-red (c) violet-yellow-brown (d) yellow-violet-brown
  32. 32.🔺 A current of 2 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
  33. 33.What does a capacitor do? (a) makes a beeping sound (b) boosts a small signal (c) limits the current (d) stores a little charge
  34. 34.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  35. 35.🔺 In the V-I-R triangle, how do we find I? (a) I = V + R (b) I = R ÷ V (c) I = V × R (d) I = V ÷ R
  36. 36.🔺 A current of 40 mA flows when 6 V is joined across a resistor. What is its resistance (in ohms)?
  37. 37.🌈 A resistor has the colour bands orange, black, brown. What is its value (in ohms)?
  38. 38.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V + I (c) P = V ÷ I (d) P = V × I
  39. 39.⚡ A 0.75 W device works on 3 V. What current does it take (in amperes)? =
  40. 40.🧾 A family uses 110 units of electricity in a month and each unit costs ₹5. What is the bill (in ₹)?

Answer key

  1. 40
  2. 500
  3. 50
  4. 1
  5. 1150
  6. 5
  7. a buzzer
  8. cathode (−)
  9. saves electricity
  10. store charge briefly
  11. 218
  12. 4.5
  13. wastes electricity
  14. 0.2
  15. 300
  16. the push of a cell
  17. watt (W)
  18. 12
  19. a motor
  20. True
  21. cathode (−)
  22. light-emitting diode
  23. red-red-red
  24. red-red-black
  25. lets current go one way
  26. close the fridge quickly
  27. R = V ÷ I
  28. 510
  29. buzzer
  30. violet-green-brown
  31. yellow-violet-brown
  32. 16
  33. stores a little charge
  34. anode (+)
  35. I = V ÷ R
  36. 150
  37. 300
  38. P = V × I
  39. 0.25
  40. 550

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