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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 453 · 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.What does a fuse do? (a) glows using little power (b) makes a beeping sound (c) blows if current is high (d) senses how hot it is
  2. 2.🌈 A gold fourth band on a resistor means the value may be off by … (a) 25 % (b) 5 % (c) 50 % (d) 0 %
  3. 3.📏 How many ohms (Ω) is 6.6 kΩ?
  4. 4.🧾 One “unit” on an electricity bill is … (a) 1 ampere (b) 1 kilowatt-hour (kWh) (c) 1 watt (d) 1 volt
  5. 5.🌈 Which band is read first on a resistor? (a) the widest gap (b) the one nearest an end (c) the gold band (d) any band
  6. 6.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 10 hours. How many watt-hours (Wh) are saved?
  7. 7.🔺 A current of 20 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
  8. 8.🔺 A current of 1.5 A flows when 4.5 V is joined across a resistor. What is its resistance (in ohms)?
  9. 9.🌈 A resistor has the colour bands yellow, violet, orange. What is its value (in ohms)?
  10. 10.🧮 Resistors of 150 Ω, 22 Ω and 50 Ω are joined in series. What is the total resistance (in ohms)?
  11. 11.🌈 A resistor has the colour bands white, yellow, red. What is its value in kilo-ohms (kΩ)? =
  12. 12.⚡ A home appliance on the 230 V mains takes 5 A. What is its power (in watts)?
  13. 13.What does a buzzer do? (a) boosts a small signal (b) turns a fan or wheels (c) makes things spin (d) makes a beeping sound
  14. 14.📏 Which unit measures the push of a cell? (a) ohm (Ω) (b) watt (W) (c) ampere (A) (d) volt (V)
  15. 15.🌈 A resistor has the colour bands green, blue, brown. What is its value (in ohms)?
  16. 16.Which of these saves electricity? (a) leave the TV on standby (b) unplug idle chargers (c) leave fridge door open (d) run fans in empty rooms
  17. 17.Which of these is measured in ohms (Ω)? (a) current (b) energy used each second (c) the flow of charge (d) resistance
  18. 18.📏 Which unit measures resistance? (a) volt (V) (b) ohm (Ω) (c) ampere (A) (d) watt (W)
  19. 19.📏 How many watts (W) is 0.4 kW?
  20. 20.📏 Voltmeter or ammeter: which one is joined across a part? (a) ammeter (b) voltmeter
  21. 21.🧮 Two resistors in parallel give a total that is … (a) always zero (b) less than either one (c) their sum (d) more than either one
  22. 22.📏 Voltmeter or ammeter: which one measures current? (a) ammeter (b) voltmeter
  23. 23.🔺 A current of 2.5 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
  24. 24.Which of these saves electricity? (a) leave the TV on standby (b) use LED lamps (c) leave fridge door open (d) iron one shirt at a time
  25. 25.Which of these is measured in volts (V)? (a) current (b) the flow of charge (c) resistance (d) voltage
  26. 26.💡 Why does an LED need a resistor in series? (a) to change its colour (b) to make it brighter (c) to store charge (d) to limit the current
  27. 27.📏 Voltmeter or ammeter: which one measures voltage? (a) voltmeter (b) ammeter
  28. 28.🌈 In the resistor colour code, which number does orange stand for?
  29. 29.🧩 Which component boosts a small signal? (a) resistor (b) transistor (c) LED (d) capacitor
  30. 30.🔺 A current of 0.5 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
  31. 31.🧩 Which part changes electrical energy into movement? (a) a motor (b) an LED (c) a fuse (d) a resistor
  32. 32.🧾 A family uses 180 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
  33. 33.🧮 Two equal 40 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  34. 34.🔺 A current of 0.5 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
  35. 35.⚡ Power tells us … (a) the colour of light (b) energy used each second (c) the length of a wire (d) the size of a cell
  36. 36.🔺 A current of 20 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
  37. 37.🧮 Resistors of 150 Ω and 33 Ω are joined in series. What is the total resistance (in ohms)?
  38. 38.💡 A blue LED uses 3 V and should get 10 mA. It runs from a 9 V supply. What resistor (in ohms) is needed in series?
  39. 39.🔺 A current of 50 mA flows when 5 V is joined across a resistor. What is its resistance (in ohms)?
  40. 40.🔍 Which is the odd one out? (a) close the fridge quickly (b) run fans in empty rooms (c) leave the TV on standby (d) iron one shirt at a time

Answer key

  1. blows if current is high
  2. 5 %
  3. 6600
  4. 1 kilowatt-hour (kWh)
  5. the one nearest an end
  6. 510
  7. 4
  8. 3
  9. 47000
  10. 222
  11. 9.4
  12. 1150
  13. makes a beeping sound
  14. volt (V)
  15. 560
  16. unplug idle chargers
  17. resistance
  18. ohm (Ω)
  19. 400
  20. voltmeter
  21. less than either one
  22. ammeter
  23. 25
  24. use LED lamps
  25. voltage
  26. to limit the current
  27. voltmeter
  28. 3
  29. transistor
  30. 1.5
  31. a motor
  32. 1620
  33. 20
  34. 10
  35. energy used each second
  36. 8
  37. 183
  38. 600
  39. 100
  40. close the fridge quickly

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