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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 536 · 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.🧮 Resistors of 68 Ω, 330 Ω, 10 Ω and 10 Ω are joined in series. What is the total resistance (in ohms)?
  2. 2.🧮 Resistors of 33 Ω and 50 Ω are joined in series. What is the total resistance (in ohms)?
  3. 3.🧩 Which component smooths a wobbly supply? (a) capacitor (b) LED (c) transistor (d) fuse
  4. 4.🔺 A current of 1 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
  5. 5.📏 Which unit measures voltage? (a) watt (W) (b) ohm (Ω) (c) ampere (A) (d) volt (V)
  6. 6.🔺 A current of 25 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
  7. 7.🧮 A 10 Ω resistor is joined in series with two equal 100 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  8. 8.What does a potentiometer do? (a) is a resistance knob (b) senses how hot it is (c) boosts a small signal (d) has coloured bands
  9. 9.📏 How many watts (W) is 3.3 kW?
  10. 10.🔺 A current of 0.5 A flows when 3 V is joined across a resistor. What is its resistance (in ohms)?
  11. 11.🧩 Which component turns a fan or wheels? (a) resistor (b) transistor (c) LED (d) motor
  12. 12.🔺 A 25 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
  13. 13.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) stays the same (b) becomes zero (c) gets bigger (d) gets smaller
  14. 14.What does a fuse do? (a) glows using little power (b) lets current go one way (c) blows if current is high (d) turns a fan or wheels
  15. 15.🧾 A family uses 190 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?
  16. 16.🔺 A current of 1 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
  17. 17.🧮 A 220 Ω resistor is joined in series with two equal 10 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
  18. 18.🔺 In the V-I-R triangle, how do we find I? (a) I = R ÷ V (b) I = V ÷ R (c) I = V + R (d) I = V × R
  19. 19.🔺 A current of 50 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
  20. 20.🔺 A 1.5 V supply is joined across a 150 Ω resistor. What current flows (in milliamperes, mA)?
  21. 21.Which of these saves electricity? (a) run fans in empty rooms (b) leave the TV on standby (c) unplug idle chargers (d) use old filament bulbs
  22. 22.True or false: an LDR stores a little charge. (a) False (b) True
  23. 23.🧮 Five equal 250 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  24. 24.🧮 Three equal 30 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  25. 25.🔍 Which is the odd one out? (a) use LED lamps (b) switch off empty rooms (c) run fans in empty rooms (d) close the fridge quickly
  26. 26.🔺 A current of 20 mA flows through a 250 Ω resistor. What is the voltage across it (in volts)? =
  27. 27.🔺 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
  28. 28.⚡ A 15 W device works on 5 V. What current does it take (in amperes)? =
  29. 29.🧾 One “unit” on an electricity bill is … (a) 1 watt (b) 1 kilowatt-hour (kWh) (c) 1 ampere (d) 1 volt
  30. 30.💡 An LED is joined to a 9 V battery with no 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
  31. 31.📏 How many watts (W) is 0.8 kW?
  32. 32.🔺 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
  33. 33.True or false: the ammeter measures voltage. (a) False (b) True
  34. 34.🔺 A 40 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
  35. 35.⚡ A home appliance on the 230 V mains takes 8 A. What is its power (in watts)?
  36. 36.💡 An LED is joined to a 6 V battery through a 330 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
  37. 37.🧮 A 33 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)?
  38. 38.📏 How many milliamperes (mA) make 1 ampere? (a) 10 (b) 1000 (c) 100 (d) 60
  39. 39.🧮 Resistors of 50 Ω, 100 Ω and 330 Ω are joined in series. What is the total resistance (in ohms)?
  40. 40.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 41 Ω resistor? (a) green-brown-black (b) yellow-brown-brown (c) yellow-brown-black (d) brown-yellow-black

Answer key

  1. 418
  2. 83
  3. capacitor
  4. 3
  5. volt (V)
  6. 5.5
  7. 60
  8. is a resistance knob
  9. 3300
  10. 6
  11. motor
  12. 2.5
  13. gets smaller
  14. blows if current is high
  15. 1330
  16. 12
  17. 225
  18. I = V ÷ R
  19. 5
  20. 10
  21. unplug idle chargers
  22. False
  23. 50
  24. 10
  25. run fans in empty rooms
  26. 5
  27. V = I × R
  28. 3
  29. 1 kilowatt-hour (kWh)
  30. may burn out
  31. 800
  32. R = V ÷ I
  33. False
  34. 2
  35. 1840
  36. does not light
  37. 268
  38. 1000
  39. 480
  40. yellow-brown-black

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