Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 448 · 40 questions

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.

1. 1.🌈 Which band is read first on a resistor? (a) the one nearest an end (b) the widest gap (c) the gold band (d) any band
2. 2.🔺 A 10 V supply is joined across a 250 Ω resistor. What current flows (in milliamperes, mA)?
3. 3.True or false: to use daylight to read saves electricity. (a) True (b) False
4. 4.🧮 Resistors of 100 Ω and 220 Ω are joined in series. What is the total resistance (in ohms)?
5. 5.What does a buzzer do? (a) blows if current is high (b) lets current go one way (c) beeps for an alarm (d) boosts a small signal
6. 6.📏 How many ohms (Ω) is 2.6 kΩ?
7. 7.🔍 Which is the odd one out? (a) use daylight to read (b) use LED lamps (c) switch off empty rooms (d) use old filament bulbs
8. 8.💡 What does LED stand for? (a) low energy device (b) large electric dial (c) light-emitting diode (d) light energy dial
9. 9.True or false: the ammeter measures current. (a) True (b) False
10. 10.🔺 A current of 2 A flows when 30 V is joined across a resistor. What is its resistance (in ohms)?
11. 11.🌈 A resistor has the colour bands grey, black, orange. What is its value in kilo-ohms (kΩ)? =
12. 12.🧮 Two resistors in parallel give a total that is … (a) more than either one (b) less than either one (c) always zero (d) their sum
13. 13.🧮 Adding another resistor in series makes the total resistance … (a) bigger (b) zero (c) smaller (d) stay the same
14. 14.Which of these saves electricity? (a) leave fridge door open (b) iron one shirt at a time (c) use old filament bulbs (d) set the AC to 24 °C
15. 15.True or false: an LED stores a little charge. (a) False (b) True
16. 16.🔍 Which is the odd one out? (a) unplug idle chargers (b) leave the TV on standby (c) use LED lamps (d) switch off empty rooms
17. 17.🔺 A current of 0.2 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
18. 18.⚡ A home appliance on the 230 V mains takes 8 A. What is its power (in watts)?
19. 19.🌈 A resistor has the colour bands red, violet, red. What is its value in kilo-ohms (kΩ)? =
20. 20.🔺 A current of 0.2 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
21. 21.True or false: the push of a cell is measured in volts (V). (a) False (b) True
22. 22.📏 How many milliamperes (mA) is 2.42 A?
23. 23.🔺 A current of 40 mA flows through a 470 Ω resistor. What is the voltage across it (in volts)? =
24. 24.⚡ Which formula gives electric power? (a) P = V ÷ I (b) P = V + I (c) P = V × I (d) P = I ÷ V
25. 25.True or false: a fuse smooths a wobbly supply. (a) False (b) True
26. 26.🔺 A current of 0.2 A flows when 2 V is joined across a resistor. What is its resistance (in ohms)?
27. 27.💡 Does it save or waste electricity to unplug idle chargers? (a) saves electricity (b) wastes electricity
28. 28.🧩 Which component senses how hot it is? (a) capacitor (b) resistor (c) fuse (d) thermistor
29. 29.📏 Which unit measures the push of a cell? (a) ampere (A) (b) ohm (Ω) (c) volt (V) (d) watt (W)
30. 30.🧾 A 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 9 hours. How many watt-hours (Wh) are saved?
31. 31.🧮 Resistors of 33 Ω, 22 Ω and 220 Ω are joined in series. What is the total resistance (in ohms)?
32. 32.🧩 Which component boosts a small signal? (a) transistor (b) resistor (c) buzzer (d) LED
33. 33.🧮 A 20 Ω resistor is joined in series with two equal 20 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
34. 34.🔺 A current of 1.5 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
35. 35.💡 Does it save or waste electricity to iron one shirt at a time? (a) wastes electricity (b) saves electricity
36. 36.What does a diode do? (a) makes things spin (b) turns a fan or wheels (c) is a resistance knob (d) lets current go one way
37. 37.True or false: a motor stores a little charge. (a) True (b) False
38. 38.🧮 A 100 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)?
39. 39.🔺 A current of 0.5 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
40. 40.🔺 A current of 20 mA flows when 10 V is joined across a resistor. What is its resistance (in ohms)?

Free electronics lessons, practice and worksheets at talentjr.in/electronics-for-kids