Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 783 · 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.🧮 Adding another resistor in series makes the total resistance … (a) smaller (b) zero (c) stay the same (d) bigger
2. 2.Which of these is measured in amperes (A)? (a) the push of a cell (b) power (c) energy used each second (d) the flow of charge
3. 3.📏 How many ohms make 1 kilo-ohm (kΩ)? (a) 1000 (b) 1024 (c) 10 (d) 100
4. 4.🔺 A current of 0.25 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
5. 5.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
6. 6.True or false: the ammeter is joined in series. (a) True (b) False
7. 7.⚡ A device works on 1.5 V and takes 0.1 A. What is its power (in watts)? =
8. 8.🔺 In the V-I-R triangle, how do we find V? (a) V = I ÷ R (b) V = R ÷ I (c) V = I × R (d) V = I + R
9. 9.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V + I (c) P = V × I (d) P = V ÷ I
10. 10.⚡ An 18 W device works on 6 V. What current does it take (in amperes)? =
11. 11.True or false: on an LED, the leg by the flat edge is the cathode (−). (a) True (b) False
12. 12.💡 What happens if an LED is put in backwards? (a) it lights brighter (b) it does not light (c) it changes colour (d) it makes a sound
13. 13.🧮 A 1.75 V battery is joined to 2 Ω and 5 Ω resistors in series. What current flows (in amperes)? =
14. 14.💡 A blue LED uses 3 V and should get 25 mA. It runs from a 5 V supply. What resistor (in ohms) is needed in series?
15. 15.📏 Voltmeter or ammeter: which one is joined across a part? (a) ammeter (b) voltmeter
16. 16.💡 Why does an LED need a resistor in series? (a) to limit the current (b) to make it brighter (c) to store charge (d) to change its colour
17. 17.🧮 Two equal 1000 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
18. 18.🧩 Which component has coloured bands? (a) resistor (b) motor (c) potentiometer (d) LDR
19. 19.🔺 A current of 3 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
20. 20.📏 How many ohms (Ω) is 2.3 kΩ?
21. 21.🧮 Two equal 220 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
22. 22.🔺 A current of 2.5 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
23. 23.📏 In the water-pipe picture of a circuit, voltage is like … (a) the pipe colour (b) the water tank lid (c) the water pressure (d) the tap handle
24. 24.📏 How many kilo-ohms (kΩ) is 7800 Ω? =
25. 25.🔺 A 12.5 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =
26. 26.True or false: to use LED lamps wastes electricity. (a) False (b) True
27. 27.🧾 A family uses 60 units of electricity in a month and each unit costs ₹5. What is the bill (in ₹)?
28. 28.🌈 A resistor has the colour bands brown, red, brown. What is its value (in ohms)?
29. 29.True or false: on an LED, the round-side leg is the cathode (−). (a) True (b) False
30. 30.💡 What does LED stand for? (a) light energy dial (b) large electric dial (c) light-emitting diode (d) low energy device
31. 31.True or false: power is measured in watts (W). (a) False (b) True
32. 32.🌈 In the resistor colour code, which number does brown stand for?
33. 33.True or false: on an LED, the longer leg is the cathode (−). (a) True (b) False
34. 34.🔺 A 1.5 V supply is joined across a 6 Ω resistor. What current flows (in amperes)? =
35. 35.📏 How many milliamperes (mA) is 1.8 A?
36. 36.🔺 A current of 20 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
37. 37.🔺 An 11 V supply is joined across a 220 Ω resistor. What current flows (in milliamperes, mA)?
38. 38.🧩 A capacitor in a circuit can … (a) make light (b) measure heat (c) store charge briefly (d) spin a wheel
39. 39.📏 How many milliamperes (mA) is 0.16 A?
40. 40.🧩 Which part changes electrical energy into movement? (a) an LED (b) a fuse (c) a resistor (d) a motor

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