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Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 892 · 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 capacitor in a circuit can … (a) make light (b) spin a wheel (c) measure heat (d) store charge briefly
  2. 2.📏 In the water-pipe picture of a circuit, resistance is like … (a) the water pressure (b) the flow of water (c) a narrow pipe (d) a bigger tank
  3. 3.⚡ A home appliance on the 230 V mains takes 8 A. What is its power (in watts)?
  4. 4.🧩 Which component is a resistance knob? (a) buzzer (b) LED (c) potentiometer (d) LDR
  5. 5.🧮 Adding another resistor in series makes the total resistance … (a) bigger (b) smaller (c) stay the same (d) zero
  6. 6.True or false: to unplug idle chargers wastes electricity. (a) False (b) True
  7. 7.🧮 A 7.5 V battery is joined to 3 Ω and 12 Ω resistors in series. What current flows (in amperes)? =
  8. 8.⚡ A 0.9 W device works on 9 V. What current does it take (in amperes)? =
  9. 9.🧾 A family uses 60 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
  10. 10.⚡ Power tells us … (a) the size of a cell (b) the length of a wire (c) the colour of light (d) energy used each second
  11. 11.💡 A red LED (it uses 2 V) is joined with a 300 Ω resistor to a 6.5 V supply. What current flows (in mA)?
  12. 12.⚡ Which formula gives electric power? (a) P = V + I (b) P = V × I (c) P = I ÷ V (d) P = V ÷ I
  13. 13.📏 Which unit measures current? (a) ohm (Ω) (b) volt (V) (c) ampere (A) (d) watt (W)
  14. 14.🧮 Resistors of 47 Ω, 330 Ω, 68 Ω and 220 Ω are joined in series. What is the total resistance (in ohms)?
  15. 15.🧩 Which component blows if current is high? (a) capacitor (b) potentiometer (c) fuse (d) transistor
  16. 16.🔺 A current of 10 mA flows when 1 V is joined across a resistor. What is its resistance (in ohms)?
  17. 17.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 31 Ω resistor? (a) yellow-brown-black (b) orange-brown-black (c) brown-orange-black (d) orange-brown-brown
  18. 18.🔺 A current of 0.2 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
  19. 19.True or false: the voltmeter measures voltage. (a) False (b) True
  20. 20.📏 How many kilowatts (kW) is 4000 W? =
  21. 21.🌈 A resistor has the colour bands blue, white, yellow. What is its value in kilo-ohms (kΩ)? =
  22. 22.🔺 A current of 10 mA flows through a 300 Ω resistor. What is the voltage across it (in volts)? =
  23. 23.🔍 Which is the odd one out? (a) run fans in empty rooms (b) leave the TV on standby (c) use LED lamps (d) use old filament bulbs
  24. 24.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 52000 Ω resistor? (a) green-red-yellow (b) red-green-orange (c) green-red-red (d) green-red-orange
  25. 25.🧮 Resistors of 10 Ω, 470 Ω, 22 Ω and 33 Ω are joined in series. What is the total resistance (in ohms)?
  26. 26.🧮 A 6 V battery is joined to 8 Ω and 4 Ω resistors in series. What current flows (in amperes)? =
  27. 27.What does an LED do? (a) stores a little charge (b) makes a beeping sound (c) has coloured bands (d) glows using little power
  28. 28.💡 Does it save or waste electricity to leave fridge door open? (a) wastes electricity (b) saves electricity
  29. 29.🧩 Which part changes electrical energy into movement? (a) a motor (b) a fuse (c) a resistor (d) an LED
  30. 30.🌈 A resistor has the colour bands blue, grey, brown. What is its value (in ohms)?
  31. 31.🧾 A 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 3 hours. How many watt-hours (Wh) are saved?
  32. 32.📏 In the water-pipe picture of a circuit, voltage is like … (a) the water pressure (b) the tap handle (c) the pipe colour (d) the water tank lid
  33. 33.Which of these is measured in volts (V)? (a) the flow of charge (b) current (c) voltage (d) energy used each second
  34. 34.⚡ A home appliance on the 230 V mains takes 4 A. What is its power (in watts)?
  35. 35.🔺 A 15 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
  36. 36.🔺 A 6 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
  37. 37.🌈 A resistor has the colour bands yellow, grey, black. What is its value (in ohms)?
  38. 38.🧾 One “unit” on an electricity bill is … (a) 1 volt (b) 1 kilowatt-hour (kWh) (c) 1 watt (d) 1 ampere
  39. 39.💡 What happens if an LED is put in backwards? (a) it does not light (b) it changes colour (c) it lights brighter (d) it makes a sound
  40. 40.🔺 A current of 0.2 A flows when 4 V is joined across a resistor. What is its resistance (in ohms)?

Answer key

  1. store charge briefly
  2. a narrow pipe
  3. 1840
  4. potentiometer
  5. bigger
  6. False
  7. 0.5
  8. 0.1
  9. 540
  10. energy used each second
  11. 15
  12. P = V × I
  13. ampere (A)
  14. 665
  15. fuse
  16. 100
  17. orange-brown-black
  18. 4
  19. True
  20. 4
  21. 690
  22. 3
  23. use LED lamps
  24. green-red-orange
  25. 535
  26. 0.5
  27. glows using little power
  28. wastes electricity
  29. a motor
  30. 680
  31. 255
  32. the water pressure
  33. voltage
  34. 920
  35. 1.5
  36. 3
  37. 48
  38. 1 kilowatt-hour (kWh)
  39. it does not light
  40. 20

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