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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 541 · 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 device works on 6 V and takes 0.2 A. What is its power (in watts)? =
  2. 2.🧮 A 2.8 V battery is joined to 12 Ω and 2 Ω resistors in series. What current flows (in amperes)? =
  3. 3.📏 Which unit measures voltage? (a) volt (V) (b) ohm (Ω) (c) ampere (A) (d) watt (W)
  4. 4.📏 How many watts (W) is 4.1 kW?
  5. 5.Which of these is measured in watts (W)? (a) current (b) power (c) the push of a cell (d) resistance
  6. 6.🔺 In the V-I-R triangle, how do we find R? (a) R = V × I (b) R = I ÷ V (c) R = V + I (d) R = V ÷ I
  7. 7.🔺 In the V-I-R triangle, how do we find V? (a) V = R ÷ I (b) V = I ÷ R (c) V = I × R (d) V = I + R
  8. 8.🌈 A resistor has the colour bands brown, orange, red. What is its value in kilo-ohms (kΩ)? =
  9. 9.🧩 Which component boosts a small signal? (a) motor (b) transistor (c) diode (d) potentiometer
  10. 10.🔺 A current of 50 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
  11. 11.🔺 A current of 50 mA flows through a 120 Ω resistor. What is the voltage across it (in volts)? =
  12. 12.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 27 Ω resistor? (a) red-violet-brown (b) orange-violet-black (c) violet-red-black (d) red-violet-black
  13. 13.🔺 A current of 1 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
  14. 14.🔺 A current of 0.25 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
  15. 15.🔺 A current of 25 mA flows when 5 V is joined across a resistor. What is its resistance (in ohms)?
  16. 16.🔺 A current of 0.1 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
  17. 17.🧩 Which component makes a beeping sound? (a) motor (b) buzzer (c) fuse (d) capacitor
  18. 18.⚡ An 18 W device works on 9 V. What current does it take (in amperes)? =
  19. 19.🧩 Which part changes electrical energy into movement? (a) a resistor (b) a fuse (c) a motor (d) an LED
  20. 20.📏 Which unit measures energy used each second? (a) volt (V) (b) watt (W) (c) ohm (Ω) (d) ampere (A)
  21. 21.🧮 Resistors of 47 Ω and 470 Ω are joined in series. What is the total resistance (in ohms)?
  22. 22.⚡ Which formula gives electric power? (a) P = V × I (b) P = V ÷ I (c) P = V + I (d) P = I ÷ V
  23. 23.📏 How many milliamperes (mA) is 0.36 A?
  24. 24.⚡ A 24 W device works on 12 V. What current does it take (in amperes)? =
  25. 25.🧮 Two resistors in parallel give a total that is … (a) less than either one (b) always zero (c) more than either one (d) their sum
  26. 26.🧾 A 40 W filament bulb is swapped for a 6 W LED lamp that gives about the same light. Both would run for 3 hours. How many watt-hours (Wh) are saved?
  27. 27.🧮 Two equal 40 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  28. 28.📏 How many ohms make 1 kilo-ohm (kΩ)? (a) 10 (b) 100 (c) 1024 (d) 1000
  29. 29.🌈 A resistor has the colour bands blue, blue, brown. What is its value (in ohms)?
  30. 30.📏 Which unit measures the push of a cell? (a) watt (W) (b) ampere (A) (c) ohm (Ω) (d) volt (V)
  31. 31.🔺 A current of 25 mA flows when 2.5 V is joined across a resistor. What is its resistance (in ohms)?
  32. 32.🌈 A resistor has the colour bands orange, blue, brown. What is its value (in ohms)?
  33. 33.🔺 A 37.5 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
  34. 34.🔺 A current of 2.5 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
  35. 35.⚡ A device works on 3 V and takes 1.5 A. What is its power (in watts)? =
  36. 36.📏 Voltmeter or ammeter: which one measures current? (a) voltmeter (b) ammeter
  37. 37.🧾 A family uses 170 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
  38. 38.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 2100 Ω resistor? (a) brown-red-red (b) red-brown-brown (c) red-brown-orange (d) red-brown-red
  39. 39.💡 An LED is joined to a 9 V battery through a 220 Ω resistor; its long leg goes to the + side and its short leg to the − side. What happens? (a) may burn out (b) lights up (c) does not light
  40. 40.🧩 Which component limits the current? (a) resistor (b) buzzer (c) capacitor (d) thermistor

Answer key

  1. 1.2
  2. 0.2
  3. volt (V)
  4. 4100
  5. power
  6. R = V ÷ I
  7. V = I × R
  8. 1.3
  9. transistor
  10. 10
  11. 6
  12. red-violet-black
  13. 4
  14. 0.75
  15. 200
  16. 0.3
  17. buzzer
  18. 2
  19. a motor
  20. watt (W)
  21. 517
  22. P = V × I
  23. 360
  24. 2
  25. less than either one
  26. 102
  27. 20
  28. 1000
  29. 660
  30. volt (V)
  31. 100
  32. 360
  33. 2.5
  34. 30
  35. 4.5
  36. ammeter
  37. 680
  38. red-brown-red
  39. lights up
  40. resistor

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