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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 63 · 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 current of 0.25 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
  2. 2.What does a buzzer do? (a) smooths a wobbly supply (b) boosts a small signal (c) senses how hot it is (d) beeps for an alarm
  3. 3.🧮 Resistors of 220 Ω, 100 Ω and 470 Ω are joined in series. What is the total resistance (in ohms)?
  4. 4.⚡ A home appliance on the 230 V mains takes 2 A. What is its power (in watts)?
  5. 5.🔺 A current of 0.2 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
  6. 6.🔺 A current of 1.5 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
  7. 7.🔺 In the V-I-R triangle, how do we find V? (a) V = I ÷ R (b) V = I × R (c) V = R ÷ I (d) V = I + R
  8. 8.📏 How many ohms (Ω) is 4 kΩ?
  9. 9.🧾 One “unit” on an electricity bill is … (a) 1 volt (b) 1 kilowatt-hour (kWh) (c) 1 watt (d) 1 ampere
  10. 10.🧩 Which component limits the current? (a) transistor (b) resistor (c) diode (d) LDR
  11. 11.🔍 Which is the odd one out? (a) close the fridge quickly (b) switch off empty rooms (c) set the AC to 24 °C (d) use old filament bulbs
  12. 12.📏 In the water-pipe picture of a circuit, current is like … (a) the flow of water (b) a narrow pipe (c) the pipe colour (d) the water pressure
  13. 13.🌈 In the resistor colour code, which number does grey stand for?
  14. 14.🌈 A resistor has the colour bands green, green, yellow. What is its value in kilo-ohms (kΩ)? =
  15. 15.⚡ Which formula gives electric power? (a) P = V × I (b) P = V ÷ I (c) P = I ÷ V (d) P = V + I
  16. 16.🧾 A 2000 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
  17. 17.🧩 Which component turns a fan or wheels? (a) LED (b) LDR (c) diode (d) motor
  18. 18.🔺 A current of 40 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
  19. 19.True or false: on an LED, the leg by the flat edge is the cathode (−). (a) False (b) True
  20. 20.Which of these is measured in amperes (A)? (a) energy used each second (b) power (c) the flow of charge (d) voltage
  21. 21.🧮 Three equal 300 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  22. 22.🧩 Which component glows using little power? (a) transistor (b) potentiometer (c) thermistor (d) LED
  23. 23.🧮 Two equal 40 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  24. 24.🔺 A 16.5 V supply is joined across a 330 Ω resistor. What current flows (in milliamperes, mA)?
  25. 25.🧮 Four equal 100 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  26. 26.🌈 In the resistor colour code, which number does brown stand for?
  27. 27.What does an LED do? (a) smooths a wobbly supply (b) limits the current (c) blows if current is high (d) glows using little power
  28. 28.🔺 A current of 25 mA flows through a 250 Ω resistor. What is the voltage across it (in volts)? =
  29. 29.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  30. 30.🧮 A 15 V battery is joined to 3 Ω and 12 Ω resistors in series. What current flows (in amperes)? =
  31. 31.🧾 A family uses 120 units of electricity in a month and each unit costs ₹5. What is the bill (in ₹)?
  32. 32.🔺 A 30 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
  33. 33.🔺 A current of 0.2 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
  34. 34.⚡ 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
  35. 35.🧩 Which component makes things spin? (a) diode (b) potentiometer (c) buzzer (d) motor
  36. 36.🔺 A current of 10 mA flows when 3 V is joined across a resistor. What is its resistance (in ohms)?
  37. 37.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
  38. 38.🌈 A resistor has the colour bands orange, white, red. What is its value (in ohms)?
  39. 39.🧩 Which component lets current go one way? (a) buzzer (b) motor (c) thermistor (d) diode
  40. 40.Which of these is measured in volts (V)? (a) current (b) how much a part resists (c) power (d) the push of a cell

Answer key

  1. 0.75
  2. beeps for an alarm
  3. 790
  4. 460
  5. 1.2
  6. 6
  7. V = I × R
  8. 4000
  9. 1 kilowatt-hour (kWh)
  10. resistor
  11. use old filament bulbs
  12. the flow of water
  13. 8
  14. 550
  15. P = V × I
  16. 20
  17. motor
  18. 4
  19. True
  20. the flow of charge
  21. 100
  22. LED
  23. 20
  24. 50
  25. 25
  26. 1
  27. glows using little power
  28. 6.25
  29. cathode (−)
  30. 1
  31. 600
  32. 2
  33. 0.4
  34. energy used each second
  35. motor
  36. 300
  37. anode (+)
  38. 3900
  39. diode
  40. the push of a cell

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