Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 560 · 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.📏 How many amperes (A) is 2780 mA? =
2. 2.🔺 A 6.6 V supply is joined across a 330 Ω resistor. What current flows (in milliamperes, mA)?
3. 3.💡 Does it save or waste electricity to run fans in empty rooms? (a) saves electricity (b) wastes electricity
4. 4.🔍 Which is the odd one out? (a) use old filament bulbs (b) switch off empty rooms (c) leave fridge door open (d) leave the TV on standby
5. 5.📏 How many milliamperes (mA) is 2.07 A?
6. 6.🧮 A 7 V battery is joined to 6 Ω and 8 Ω resistors in series. What current flows (in amperes)? =
7. 7.🔺 A current of 3 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
8. 8.🔺 A current of 3 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
9. 9.🧾 One “unit” on an electricity bill is … (a) 1 watt (b) 1 ampere (c) 1 kilowatt-hour (kWh) (d) 1 volt
10. 10.🔺 A current of 0.2 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
11. 11.🧩 Which component glows using little power? (a) diode (b) thermistor (c) LED (d) capacitor
12. 12.⚡ Which formula gives electric power? (a) P = V ÷ I (b) P = V × I (c) P = V + I (d) P = I ÷ V
13. 13.🔺 A current of 50 mA flows when 10 V is joined across a resistor. What is its resistance (in ohms)?
14. 14.📏 Which unit measures voltage? (a) watt (W) (b) ampere (A) (c) volt (V) (d) ohm (Ω)
15. 15.💡 Why does an LED need a resistor in series? (a) to make it brighter (b) to change its colour (c) to limit the current (d) to store charge
16. 16.🧩 Which part changes electrical energy into sound? (a) a capacitor (b) a diode (c) a buzzer (d) a resistor
17. 17.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) stays the same (b) becomes zero (c) gets smaller (d) gets bigger
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.📏 Which unit measures resistance? (a) volt (V) (b) ampere (A) (c) ohm (Ω) (d) watt (W)
20. 20.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
21. 21.🧮 Adding another resistor in series makes the total resistance … (a) stay the same (b) smaller (c) bigger (d) zero
22. 22.🌈 A gold fourth band on a resistor means the value may be off by … (a) 0 % (b) 5 % (c) 25 % (d) 50 %
23. 23.🧩 Which part changes electrical energy into movement? (a) a motor (b) an LED (c) a resistor (d) a fuse
24. 24.🔺 A 1.5 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
25. 25.🌈 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
26. 26.🔺 A current of 1.5 A flows when 22.5 V is joined across a resistor. What is its resistance (in ohms)?
27. 27.🧮 Four equal 400 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
28. 28.🔺 A current of 2.5 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
29. 29.💡 What happens if an LED is put in backwards? (a) it lights brighter (b) it changes colour (c) it makes a sound (d) it does not light
30. 30.📏 Voltmeter or ammeter: which one measures voltage? (a) ammeter (b) voltmeter
31. 31.True or false: power is measured in volts (V). (a) True (b) False
32. 32.🔺 A current of 0.2 A flows when 0.8 V is joined across a resistor. What is its resistance (in ohms)?
33. 33.🌈 In the resistor colour code, which number does yellow stand for?
34. 34.🧮 Resistors of 68 Ω and 220 Ω are joined in series. What is the total resistance (in ohms)?
35. 35.🧮 Three equal 75 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
36. 36.🔺 A current of 25 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
37. 37.🔺 A current of 20 mA flows when 9.4 V is joined across a resistor. What is its resistance (in ohms)?
38. 38.True or false: energy used each second is measured in amperes (A). (a) True (b) False
39. 39.📏 How many kilowatts (kW) is 3200 W? =
40. 40.🌈 A resistor has the colour bands yellow, orange, orange. What is its value in kilo-ohms (kΩ)? =

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