Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 10 · 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.🧮 A 1.3 V battery is joined to 8 Ω and 5 Ω resistors in series. What current flows (in amperes)? =
2. 2.Which of these is measured in volts (V)? (a) the flow of charge (b) the push of a cell (c) resistance (d) current
3. 3.🧾 A 250 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
4. 4.True or false: power is measured in amperes (A). (a) True (b) False
5. 5.🌈 In the resistor colour code, which number does grey stand for?
6. 6.⚡ A 27 W device works on 9 V. What current does it take (in amperes)? =
7. 7.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
8. 8.Which of these wastes electricity? (a) use LED lamps (b) switch off empty rooms (c) iron one shirt at a time (d) use daylight to read
9. 9.⚡ A device works on 3 V and takes 2 A. What is its power (in watts)? =
10. 10.⚡ A home appliance on the 230 V mains takes 2 A. What is its power (in watts)?
11. 11.True or false: on an LED, the shorter leg is the anode (+). (a) True (b) False
12. 12.🔺 A current of 25 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
13. 13.🧾 A family uses 180 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
14. 14.📏 How many watts (W) is 3.7 kW?
15. 15.Which of these saves electricity? (a) leave fridge door open (b) iron one shirt at a time (c) unplug idle chargers (d) leave the TV on standby
16. 16.🌈 A resistor has the colour bands blue, white, brown. What is its value (in ohms)?
17. 17.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 71 Ω resistor? (a) violet-brown-brown (b) violet-brown-black (c) grey-brown-black (d) brown-violet-black
18. 18.🌈 Which band is read first on a resistor? (a) the widest gap (b) the one nearest an end (c) the gold band (d) any band
19. 19.🔺 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
20. 20.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) becomes zero (b) stays the same (c) gets smaller (d) gets bigger
21. 21.📏 How many kilo-ohms (kΩ) is 8800 Ω? =
22. 22.⚡ A device works on 24 V and takes 3 A. What is its power (in watts)? =
23. 23.🔺 A current of 25 mA flows when 3.75 V is joined across a resistor. What is its resistance (in ohms)?
24. 24.🧮 A 15 V battery is joined to 3 Ω and 12 Ω resistors in series. What current flows (in amperes)? =
25. 25.🌈 A resistor has the colour bands yellow, grey, orange. What is its value (in ohms)?
26. 26.True or false: resistance is measured in ohms (Ω). (a) False (b) True
27. 27.🧩 Which component makes things spin? (a) capacitor (b) motor (c) resistor (d) LED
28. 28.🔍 Which is the odd one out? (a) leave fridge door open (b) leave the TV on standby (c) unplug idle chargers (d) iron one shirt at a time
29. 29.🧾 A 250 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
30. 30.🔺 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
31. 31.🌈 In the resistor colour code, which number does violet stand for?
32. 32.🌈 In the resistor colour code, which number does yellow stand for?
33. 33.💡 Why does an LED need a resistor in series? (a) to limit the current (b) to change its colour (c) to make it brighter (d) to store charge
34. 34.🔺 A current of 50 mA flows when 20 V is joined across a resistor. What is its resistance (in ohms)?
35. 35.True or false: to leave the TV on standby saves electricity. (a) True (b) False
36. 36.Which of these wastes electricity? (a) unplug idle chargers (b) switch off empty rooms (c) run fans in empty rooms (d) use LED lamps
37. 37.🌈 In the resistor colour code, which number does brown stand for?
38. 38.🧮 Adding another resistor in series makes the total resistance … (a) stay the same (b) zero (c) smaller (d) bigger
39. 39.📏 How many amperes (A) is 790 mA? =
40. 40.🌈 In the resistor colour code, which number does black stand for?

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