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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 913 · 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 220 Ω, 47 Ω, 330 Ω and 20 Ω are joined in series. What is the total resistance (in ohms)?
  2. 2.True or false: a motor is a resistance knob. (a) False (b) True
  3. 3.🧮 Two resistors in parallel give a total that is … (a) less than either one (b) their sum (c) more than either one (d) always zero
  4. 4.🌈 A gold fourth band on a resistor means the value may be off by … (a) 0 % (b) 25 % (c) 5 % (d) 50 %
  5. 5.🔺 A current of 25 mA flows when 10 V is joined across a resistor. What is its resistance (in ohms)?
  6. 6.🧮 A 0.6 V battery is joined to 2 Ω and 4 Ω resistors in series. What current flows (in amperes)? =
  7. 7.🔺 A 60 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
  8. 8.🔺 A current of 2.5 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
  9. 9.📏 How many milliamperes (mA) is 1.24 A?
  10. 10.🌈 Which band is read first on a resistor? (a) the gold band (b) the widest gap (c) the one nearest an end (d) any band
  11. 11.📏 In the water-pipe picture of a circuit, current is like … (a) the flow of water (b) the water pressure (c) a narrow pipe (d) the pipe colour
  12. 12.True or false: voltage is measured in volts (V). (a) True (b) False
  13. 13.🔺 A current of 2.5 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
  14. 14.🔺 A current of 25 mA flows through a 470 Ω resistor. What is the voltage across it (in volts)? =
  15. 15.🔺 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
  16. 16.🌈 In the resistor colour code, which number does blue stand for?
  17. 17.🔺 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
  18. 18.🧩 Which component makes a beeping sound? (a) diode (b) capacitor (c) buzzer (d) resistor
  19. 19.💡 An LED is joined to a 9 V battery through a 330 Ω resistor; the leg next to the flat edge of its rim goes to the + side. What happens? (a) lights up (b) may burn out (c) does not light
  20. 20.True or false: an LED glows using little power. (a) True (b) False
  21. 21.True or false: a buzzer beeps for an alarm. (a) False (b) True
  22. 22.⚡ Which formula gives electric power? (a) P = V × I (b) P = V + I (c) P = I ÷ V (d) P = V ÷ I
  23. 23.🧩 Which component has coloured bands? (a) thermistor (b) motor (c) transistor (d) resistor
  24. 24.🔺 A 2.5 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
  25. 25.🔺 A current of 0.2 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
  26. 26.📏 How many ohms (Ω) is 5.2 kΩ?
  27. 27.🧮 Resistors of 22 Ω, 100 Ω, 33 Ω and 20 Ω are joined in series. What is the total resistance (in ohms)?
  28. 28.🧩 Which component senses how bright it is? (a) transistor (b) LED (c) LDR (d) potentiometer
  29. 29.📏 Which unit measures the flow of charge? (a) watt (W) (b) ampere (A) (c) ohm (Ω) (d) volt (V)
  30. 30.⚡ A home appliance on the 230 V mains takes 1 A. What is its power (in watts)?
  31. 31.⚡ A device works on 5 V and takes 0.2 A. What is its power (in watts)? =
  32. 32.What does a potentiometer do? (a) lets current go one way (b) is a resistance knob (c) turns a fan or wheels (d) limits the current
  33. 33.🔺 A current of 10 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
  34. 34.🔺 A 5 V supply is joined across a 250 Ω resistor. What current flows (in milliamperes, mA)?
  35. 35.True or false: the flow of charge is measured in watts (W). (a) False (b) True
  36. 36.🔺 A 24 V supply is joined across a 12 Ω resistor. What current flows (in amperes)? =
  37. 37.True or false: a fuse makes a beeping sound. (a) False (b) True
  38. 38.🧮 A 150 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)?
  39. 39.🧮 Three equal 15 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
  40. 40.What does an LED do? (a) smooths a wobbly supply (b) glows using little power (c) makes a beeping sound (d) stores a little charge

Answer key

  1. 617
  2. False
  3. less than either one
  4. 5 %
  5. 400
  6. 0.1
  7. 3
  8. 10
  9. 1240
  10. the one nearest an end
  11. the flow of water
  12. True
  13. 7.5
  14. 11.75
  15. R = V ÷ I
  16. 6
  17. I = V ÷ R
  18. buzzer
  19. does not light
  20. True
  21. True
  22. P = V × I
  23. resistor
  24. 0.25
  25. 0.8
  26. 5200
  27. 175
  28. LDR
  29. ampere (A)
  30. 230
  31. 1
  32. is a resistance knob
  33. 4
  34. 20
  35. False
  36. 2
  37. False
  38. 155
  39. 5
  40. glows using little power

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