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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 741 · 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.

NameDateTime takenScore ___ / 40
  1. 1.📏 How many kilowatts (kW) is 1500 W? =
  2. 2.🔺 In the V-I-R triangle, how do we find V? (a) V = I ÷ R (b) V = I + R (c) V = I × R (d) V = R ÷ I
  3. 3.🧮 A 47 Ω resistor is joined in series with two equal 1000 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  4. 4.⚡ Power tells us … (a) the size of a cell (b) the colour of light (c) energy used each second (d) the length of a wire
  5. 5.🔺 A 0.5 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
  6. 6.🔺 A 15 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =
  7. 7.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 36 Ω resistor? (a) orange-blue-brown (b) blue-orange-black (c) yellow-blue-black (d) orange-blue-black
  8. 8.💡 Does it save or waste electricity to use LED lamps? (a) saves electricity (b) wastes electricity
  9. 9.⚡ A home appliance on the 230 V mains takes 1 A. What is its power (in watts)?
  10. 10.🔺 A 6 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
  11. 11.True or false: on an LED, the longer leg is the cathode (−). (a) True (b) False
  12. 12.True or false: the voltmeter is joined across a part. (a) False (b) True
  13. 13.🧮 Adding another resistor in series makes the total resistance … (a) stay the same (b) zero (c) smaller (d) bigger
  14. 14.🔺 In the V-I-R triangle, how do we find I? (a) I = V ÷ R (b) I = V + R (c) I = R ÷ V (d) I = V × R
  15. 15.🧮 Resistors of 33 Ω and 22 Ω are joined in series. What is the total resistance (in ohms)?
  16. 16.Which of these wastes electricity? (a) set the AC to 24 °C (b) unplug idle chargers (c) switch off empty rooms (d) use old filament bulbs
  17. 17.True or false: to use daylight to read saves electricity. (a) False (b) True
  18. 18.True or false: on an LED, the round-side leg is the cathode (−). (a) True (b) False
  19. 19.🧩 Which component blows if current is high? (a) motor (b) fuse (c) capacitor (d) LED
  20. 20.🧮 Two equal 40 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  21. 21.🔺 A current of 0.2 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
  22. 22.🧾 A 250 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
  23. 23.🧩 Which component has coloured bands? (a) transistor (b) LED (c) potentiometer (d) resistor
  24. 24.🔺 A current of 10 mA flows when 2.5 V is joined across a resistor. What is its resistance (in ohms)?
  25. 25.🧾 A family uses 40 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
  26. 26.🧮 Two resistors in parallel give a total that is … (a) less than either one (b) more than either one (c) always zero (d) their sum
  27. 27.💡 A red LED (it uses 2 V) is joined with a 300 Ω resistor to a 3.5 V supply. What current flows (in mA)?
  28. 28.📏 Which unit measures energy used each second? (a) ampere (A) (b) watt (W) (c) volt (V) (d) ohm (Ω)
  29. 29.🔺 A current of 50 mA flows through a 120 Ω resistor. What is the voltage across it (in volts)? =
  30. 30.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  31. 31.🔺 A current of 0.2 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
  32. 32.💡 An LED is joined to a 5 V battery through a 330 Ω resistor; its long leg goes to the + side and its short leg to the − side. What happens? (a) may burn out (b) lights up (c) does not light
  33. 33.🔺 A current of 0.5 A flows when 2.5 V is joined across a resistor. What is its resistance (in ohms)?
  34. 34.📏 In the water-pipe picture of a circuit, current is like … (a) the flow of water (b) a narrow pipe (c) the water pressure (d) the pipe colour
  35. 35.What does a buzzer do? (a) glows using little power (b) makes a beeping sound (c) turns a fan or wheels (d) senses how hot it is
  36. 36.⚡ A home appliance on the 230 V mains takes 1.5 A. What is its power (in watts)?
  37. 37.🔺 A 0.75 V supply is joined across a 3 Ω resistor. What current flows (in amperes)? =
  38. 38.What does a motor do? (a) lets current go one way (b) blows if current is high (c) stores a little charge (d) turns a fan or wheels
  39. 39.🔺 A current of 25 mA flows when 2.5 V is joined across a resistor. What is its resistance (in ohms)?
  40. 40.🔺 In the V-I-R triangle, how do we find R? (a) R = I ÷ V (b) R = V × I (c) R = V + I (d) R = V ÷ I

Answer key

  1. 1.5
  2. V = I × R
  3. 547
  4. energy used each second
  5. 0.25
  6. 3
  7. orange-blue-black
  8. saves electricity
  9. 230
  10. 1.5
  11. False
  12. True
  13. bigger
  14. I = V ÷ R
  15. 55
  16. use old filament bulbs
  17. True
  18. False
  19. fuse
  20. 20
  21. 4
  22. 2.5
  23. resistor
  24. 250
  25. 360
  26. less than either one
  27. 5
  28. watt (W)
  29. 6
  30. cathode (−)
  31. 0.6
  32. lights up
  33. 5
  34. the flow of water
  35. makes a beeping sound
  36. 345
  37. 0.25
  38. turns a fan or wheels
  39. 100
  40. R = V ÷ I

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