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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 656 · 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.🔺 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
  2. 2.⚡ A 24 W device works on 12 V. What current does it take (in amperes)? =
  3. 3.📏 How many kilowatts (kW) is 550 W? =
  4. 4.🔺 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
  5. 5.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  6. 6.💡 An LED is joined to a 6 V battery through a 220 Ω resistor; the leg next to the flat edge of its rim goes to the + side. What happens? (a) does not light (b) may burn out (c) lights up
  7. 7.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  8. 8.🔺 A current of 0.1 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
  9. 9.🌈 In the resistor colour code, which number does brown stand for?
  10. 10.⚡ A home appliance on the 230 V mains takes 8 A. What is its power (in watts)?
  11. 11.📏 In the water-pipe picture of a circuit, current is like … (a) the water pressure (b) the pipe colour (c) a narrow pipe (d) the flow of water
  12. 12.💡 A red LED uses 2 V and should get 10 mA. It runs from a 5 V supply. What resistor (in ohms) is needed in series?
  13. 13.🔺 A 4 V supply is joined across a 100 Ω resistor. What current flows (in milliamperes, mA)?
  14. 14.🧮 Three equal 15 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  15. 15.🔺 A current of 0.25 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
  16. 16.📏 Voltmeter or ammeter: which one measures voltage? (a) voltmeter (b) ammeter
  17. 17.🧩 Which part changes electrical energy into movement? (a) a fuse (b) a resistor (c) a motor (d) an LED
  18. 18.🔺 A current of 0.2 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
  19. 19.🔺 A 15 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =
  20. 20.🧮 Two resistors in parallel give a total that is … (a) always zero (b) less than either one (c) more than either one (d) their sum
  21. 21.🧮 Three equal 300 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  22. 22.🧩 Which part changes electrical energy into sound? (a) a diode (b) a buzzer (c) a capacitor (d) a resistor
  23. 23.Which of these is measured in ohms (Ω)? (a) the push of a cell (b) the flow of charge (c) current (d) resistance
  24. 24.🧾 A family uses 170 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
  25. 25.Which of these is measured in watts (W)? (a) current (b) the push of a cell (c) power (d) resistance
  26. 26.🧾 A 50 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
  27. 27.📏 How many watts (W) is 2 kW?
  28. 28.💡 A red LED (it uses 2 V) is joined with a 100 Ω resistor to a 4 V supply. What current flows (in mA)?
  29. 29.🌈 A resistor has the colour bands red, orange, black. What is its value (in ohms)?
  30. 30.💡 A red LED (it uses 2 V) is joined with a 200 Ω resistor to a 4 V supply. What current flows (in mA)?
  31. 31.True or false: a transistor smooths a wobbly supply. (a) False (b) True
  32. 32.⚡ A device works on 5 V and takes 1.5 A. What is its power (in watts)? =
  33. 33.True or false: the push of a cell is measured in volts (V). (a) True (b) False
  34. 34.True or false: resistance is measured in ohms (Ω). (a) True (b) False
  35. 35.🔺 A current of 3 A flows when 12 V is joined across a resistor. What is its resistance (in ohms)?
  36. 36.🌈 A resistor has the colour bands orange, black, orange. What is its value in kilo-ohms (kΩ)? =
  37. 37.True or false: an LED smooths a wobbly supply. (a) False (b) True
  38. 38.⚡ A 36 W device works on 24 V. What current does it take (in amperes)? =
  39. 39.⚡ Power tells us … (a) the length of a wire (b) energy used each second (c) the size of a cell (d) the colour of light
  40. 40.What does a resistor do? (a) smooths a wobbly supply (b) beeps for an alarm (c) is a resistance knob (d) has coloured bands

Answer key

  1. V = I × R
  2. 2
  3. 0.55
  4. I = V ÷ R
  5. anode (+)
  6. does not light
  7. cathode (−)
  8. 2
  9. 1
  10. 1840
  11. the flow of water
  12. 300
  13. 40
  14. 5
  15. 1.25
  16. voltmeter
  17. a motor
  18. 0.6
  19. 3
  20. less than either one
  21. 100
  22. a buzzer
  23. resistance
  24. 1530
  25. power
  26. 0.1
  27. 2000
  28. 20
  29. 23
  30. 10
  31. False
  32. 7.5
  33. True
  34. True
  35. 4
  36. 30
  37. False
  38. 1.5
  39. energy used each second
  40. has coloured bands

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