Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 661 · 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 milliamperes (mA) is 0.7 A?
2. 2.📏 Voltmeter or ammeter: which one measures voltage? (a) ammeter (b) voltmeter
3. 3.⚡ A device works on 6 V and takes 0.5 A. What is its power (in watts)? =
4. 4.🔺 A current of 25 mA flows when 12.5 V is joined across a resistor. What is its resistance (in ohms)?
5. 5.📏 Which unit measures how much a part resists? (a) watt (W) (b) ampere (A) (c) ohm (Ω) (d) volt (V)
6. 6.🔺 A current of 0.25 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
7. 7.🔺 An 11 V supply is joined across a 220 Ω resistor. What current flows (in milliamperes, mA)?
8. 8.True or false: the voltmeter is joined in series. (a) False (b) True
9. 9.🔺 In the V-I-R triangle, how do we find R? (a) R = V × I (b) R = V + I (c) R = I ÷ V (d) R = V ÷ I
10. 10.🧮 A 68 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)?
11. 11.🔺 A current of 0.25 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
12. 12.🌈 A resistor has the colour bands grey, green, red. What is its value (in ohms)?
13. 13.🔍 Which is the odd one out? (a) unplug idle chargers (b) leave the TV on standby (c) use daylight to read (d) close the fridge quickly
14. 14.💡 A red LED (it uses 2 V) is joined with a 150 Ω resistor to a 4.25 V supply. What current flows (in mA)?
15. 15.🌈 In the resistor colour code, which number does red stand for?
16. 16.🔺 In the V-I-R triangle, how do we find V? (a) V = I + R (b) V = I × R (c) V = I ÷ R (d) V = R ÷ I
17. 17.🧮 A 1.5 V battery is joined to 3 Ω and 3 Ω resistors in series. What current flows (in amperes)? =
18. 18.🔺 A current of 50 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
19. 19.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
20. 20.🧮 Resistors of 68 Ω and 47 Ω are joined in series. What is the total resistance (in ohms)?
21. 21.⚡ Which formula gives electric power? (a) P = V × I (b) P = V ÷ I (c) P = V + I (d) P = I ÷ V
22. 22.🌈 A gold fourth band on a resistor means the value may be off by … (a) 0 % (b) 5 % (c) 50 % (d) 25 %
23. 23.True or false: voltage is measured in amperes (A). (a) False (b) True
24. 24.⚡ A device works on 1.5 V and takes 0.5 A. What is its power (in watts)? =
25. 25.⚡ Power tells us … (a) the colour of light (b) energy used each second (c) the size of a cell (d) the length of a wire
26. 26.⚡ A 1.25 W device works on 5 V. What current does it take (in amperes)? =
27. 27.💡 Does it save or waste electricity to use LED lamps? (a) wastes electricity (b) saves electricity
28. 28.True or false: the ammeter is joined in series. (a) True (b) False
29. 29.🔺 A current of 1 A flows when 10 V is joined across a resistor. What is its resistance (in ohms)?
30. 30.🔺 A 2.5 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
31. 31.🔺 A current of 0.5 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
32. 32.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
33. 33.🧮 Adding another resistor in series makes the total resistance … (a) zero (b) smaller (c) bigger (d) stay the same
34. 34.📏 Voltmeter or ammeter: which one measures current? (a) voltmeter (b) ammeter
35. 35.True or false: a buzzer beeps for an alarm. (a) False (b) True
36. 36.🧩 Which part changes electrical energy into movement? (a) a motor (b) a resistor (c) a fuse (d) an LED
37. 37.💡 A red LED (it uses 2 V) is joined with a 200 Ω resistor to a 5 V supply. What current flows (in mA)?
38. 38.⚡ A home appliance on the 230 V mains takes 5 A. What is its power (in watts)?
39. 39.🔺 In the V-I-R triangle, how do we find I? (a) I = V ÷ R (b) I = V × R (c) I = V + R (d) I = R ÷ V
40. 40.🔺 A current of 50 mA flows when 6 V is joined across a resistor. What is its resistance (in ohms)?

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