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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 790 · 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.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  2. 2.🔺 A current of 3 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
  3. 3.🔺 A current of 1.5 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
  4. 4.🔺 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
  5. 5.🌈 Which band is read first on a resistor? (a) the gold band (b) any band (c) the one nearest an end (d) the widest gap
  6. 6.Which of these is measured in volts (V)? (a) how much a part resists (b) current (c) voltage (d) energy used each second
  7. 7.🔺 A current of 40 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
  8. 8.📏 In the water-pipe picture of a circuit, current is like … (a) the pipe colour (b) a narrow pipe (c) the flow of water (d) the water pressure
  9. 9.⚡ A device works on 6 V and takes 0.25 A. What is its power (in watts)? =
  10. 10.🔺 A 1.5 V supply is joined across a 150 Ω resistor. What current flows (in milliamperes, mA)?
  11. 11.🧮 Resistors of 20 Ω, 68 Ω and 50 Ω are joined in series. What is the total resistance (in ohms)?
  12. 12.Which of these saves electricity? (a) leave the TV on standby (b) use old filament bulbs (c) leave fridge door open (d) use daylight to read
  13. 13.🌈 A resistor has the colour bands violet, green, yellow. What is its value in kilo-ohms (kΩ)? =
  14. 14.🔺 A current of 3 A flows when 30 V is joined across a resistor. What is its resistance (in ohms)?
  15. 15.💡 An LED is joined to a 6 V battery through a 330 Ω resistor; the leg next to the flat edge of its rim goes to the − side. What happens? (a) may burn out (b) does not light (c) lights up
  16. 16.Which of these is measured in watts (W)? (a) voltage (b) the push of a cell (c) resistance (d) power
  17. 17.📏 How many kilowatts (kW) is 4450 W? =
  18. 18.⚡ A home appliance on the 230 V mains takes 4 A. What is its power (in watts)?
  19. 19.🧮 Three equal 30 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  20. 20.True or false: on an LED, the shorter leg is the cathode (−). (a) True (b) False
  21. 21.🔍 Which is the odd one out? (a) switch off empty rooms (b) set the AC to 24 °C (c) use LED lamps (d) run fans in empty rooms
  22. 22.🧮 A 68 Ω resistor is joined in series with two equal 470 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  23. 23.🧮 A 1.25 V battery is joined to 2 Ω and 3 Ω resistors in series. What current flows (in amperes)? =
  24. 24.💡 Does it save or waste electricity to unplug idle chargers? (a) wastes electricity (b) saves electricity
  25. 25.🧾 One “unit” on an electricity bill is … (a) 1 watt (b) 1 volt (c) 1 kilowatt-hour (kWh) (d) 1 ampere
  26. 26.🔺 In the V-I-R triangle, how do we find V? (a) V = I × R (b) V = R ÷ I (c) V = I ÷ R (d) V = I + R
  27. 27.True or false: a transistor boosts a small signal. (a) False (b) True
  28. 28.🧩 Which component glows using little power? (a) LED (b) capacitor (c) fuse (d) diode
  29. 29.🧮 Two resistors in parallel give a total that is … (a) their sum (b) more than either one (c) less than either one (d) always zero
  30. 30.🔺 A current of 0.1 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
  31. 31.⚡ A device works on 9 V and takes 0.1 A. What is its power (in watts)? =
  32. 32.🧾 A family uses 70 units of electricity in a month and each unit costs ₹5. What is the bill (in ₹)?
  33. 33.True or false: on an LED, the leg by the flat edge is the cathode (−). (a) False (b) True
  34. 34.🔺 A current of 10 mA flows through a 120 Ω resistor. What is the voltage across it (in volts)? =
  35. 35.🔺 A current of 10 mA flows when 2.5 V is joined across a resistor. What is its resistance (in ohms)?
  36. 36.📏 How many ohms (Ω) is 5.9 kΩ?
  37. 37.🔺 A 15 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
  38. 38.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
  39. 39.🔺 A current of 50 mA flows when 11 V is joined across a resistor. What is its resistance (in ohms)?
  40. 40.🔺 A current of 20 mA flows through a 500 Ω resistor. What is the voltage across it (in volts)? =

Answer key

  1. cathode (−)
  2. 30
  3. 12
  4. R = V ÷ I
  5. the one nearest an end
  6. voltage
  7. 8
  8. the flow of water
  9. 1.5
  10. 10
  11. 138
  12. use daylight to read
  13. 750
  14. 10
  15. lights up
  16. power
  17. 4.45
  18. 920
  19. 10
  20. True
  21. run fans in empty rooms
  22. 303
  23. 0.25
  24. saves electricity
  25. 1 kilowatt-hour (kWh)
  26. V = I × R
  27. True
  28. LED
  29. less than either one
  30. 0.8
  31. 0.9
  32. 350
  33. True
  34. 1.2
  35. 250
  36. 5900
  37. 1.5
  38. cathode (−)
  39. 220
  40. 10

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