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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 477 · 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 red LED uses 2 V and should get 20 mA. It runs from a 6 V supply. What resistor (in ohms) is needed in series?
  2. 2.🧾 A family uses 70 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
  3. 3.📏 How many ohms (Ω) is 1.2 kΩ?
  4. 4.🔺 A current of 1 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
  5. 5.⚡ A home appliance on the 230 V mains takes 8 A. What is its power (in watts)?
  6. 6.📏 How many ohms (Ω) is 6.2 kΩ?
  7. 7.📏 How many milliamperes (mA) make 1 ampere? (a) 60 (b) 10 (c) 1000 (d) 100
  8. 8.💡 An LED is joined to a 5 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) may burn out (c) does not light
  9. 9.📏 Voltmeter or ammeter: which one is joined in series? (a) voltmeter (b) ammeter
  10. 10.⚡ A home appliance on the 230 V mains takes 1 A. What is its power (in watts)?
  11. 11.🔺 A current of 0.1 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
  12. 12.🔺 A current of 0.25 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
  13. 13.🔺 A current of 20 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
  14. 14.🌈 Which band is read first on a resistor? (a) the widest gap (b) the gold band (c) any band (d) the one nearest an end
  15. 15.⚡ Power tells us … (a) energy used each second (b) the colour of light (c) the length of a wire (d) the size of a cell
  16. 16.Which of these wastes electricity? (a) close the fridge quickly (b) use daylight to read (c) use LED lamps (d) run fans in empty rooms
  17. 17.💡 A red LED (it uses 2 V) is joined with a 200 Ω resistor to a 4 V supply. What current flows (in mA)?
  18. 18.🌈 A resistor has the colour bands green, red, red. What is its value in kilo-ohms (kΩ)? =
  19. 19.True or false: current is measured in amperes (A). (a) False (b) True
  20. 20.🔺 A 6 V supply is joined across a 120 Ω resistor. What current flows (in milliamperes, mA)?
  21. 21.🔺 A current of 10 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
  22. 22.🔺 A current of 0.25 A flows when 5 V is joined across a resistor. What is its resistance (in ohms)?
  23. 23.🔺 A 12 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
  24. 24.📏 Which unit measures how much a part resists? (a) ampere (A) (b) ohm (Ω) (c) volt (V) (d) watt (W)
  25. 25.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) stays the same (b) gets smaller (c) gets bigger (d) becomes zero
  26. 26.💡 Does it save or waste electricity to use daylight to read? (a) saves electricity (b) wastes electricity
  27. 27.📏 In the water-pipe picture of a circuit, voltage is like … (a) the tap handle (b) the pipe colour (c) the water tank lid (d) the water pressure
  28. 28.🌈 In the resistor colour code, which number does blue stand for?
  29. 29.📏 Which unit measures current? (a) ampere (A) (b) watt (W) (c) volt (V) (d) ohm (Ω)
  30. 30.🔺 In the V-I-R triangle, how do we find R? (a) R = V + I (b) R = V ÷ I (c) R = V × I (d) R = I ÷ V
  31. 31.🔺 A current of 10 mA flows when 2 V is joined across a resistor. What is its resistance (in ohms)?
  32. 32.🔺 A current of 1.5 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
  33. 33.🧩 A capacitor in a circuit can … (a) store charge briefly (b) make light (c) spin a wheel (d) measure heat
  34. 34.📏 How many amperes (A) is 1160 mA? =
  35. 35.📏 How many watts (W) is 0.2 kW?
  36. 36.🧮 Resistors of 470 Ω and 330 Ω are joined in series. What is the total resistance (in ohms)?
  37. 37.True or false: on an LED, the round-side leg is the cathode (−). (a) True (b) False
  38. 38.🧩 Which part changes electrical energy into movement? (a) a fuse (b) a motor (c) a resistor (d) an LED
  39. 39.⚡ A home appliance on the 230 V mains takes 5 A. What is its power (in watts)?
  40. 40.🧩 Which component has coloured bands? (a) buzzer (b) capacitor (c) resistor (d) fuse

Answer key

  1. 200
  2. 280
  3. 1200
  4. 10
  5. 1840
  6. 6200
  7. 1000
  8. does not light
  9. ammeter
  10. 230
  11. 1.2
  12. 1
  13. 3
  14. the one nearest an end
  15. energy used each second
  16. run fans in empty rooms
  17. 10
  18. 5.2
  19. True
  20. 50
  21. 1.5
  22. 20
  23. 2
  24. ohm (Ω)
  25. gets smaller
  26. saves electricity
  27. the water pressure
  28. 6
  29. ampere (A)
  30. R = V ÷ I
  31. 200
  32. 15
  33. store charge briefly
  34. 1.16
  35. 200
  36. 800
  37. False
  38. a motor
  39. 1150
  40. resistor

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