Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 552 · 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.🧮 Five equal 25 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
2. 2.True or false: the ammeter is joined across a part. (a) False (b) True
3. 3.📏 How many watts (W) is 3.8 kW?
4. 4.⚡ A 1.5 W device works on 3 V. What current does it take (in amperes)? =
5. 5.🔺 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
6. 6.🧮 Two equal 200 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
7. 7.🧾 A family uses 130 units of electricity in a month and each unit costs ₹5. What is the bill (in ₹)?
8. 8.🧩 Which component blows if current is high? (a) fuse (b) potentiometer (c) motor (d) LED
9. 9.What does a resistor do? (a) is a resistance knob (b) limits the current (c) stores a little charge (d) glows using little power
10. 10.True or false: the flow of charge is measured in ohms (Ω). (a) False (b) True
11. 11.🔺 In the V-I-R triangle, how do we find V? (a) V = R ÷ I (b) V = I ÷ R (c) V = I × R (d) V = I + R
12. 12.Which of these saves electricity? (a) run fans in empty rooms (b) leave the TV on standby (c) use old filament bulbs (d) use daylight to read
13. 13.📏 How many ohms (Ω) is 1 kΩ?
14. 14.🌈 In the resistor colour code, which number does yellow stand for?
15. 15.🔺 A current of 3 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
16. 16.True or false: a potentiometer turns a fan or wheels. (a) True (b) False
17. 17.⚡ A device works on 1.5 V and takes 1.5 A. What is its power (in watts)? =
18. 18.True or false: to use daylight to read saves electricity. (a) True (b) False
19. 19.💡 An LED is joined to a 3 V battery through a 1000 Ω resistor; its long leg goes to the − side and its short leg to the + side. What happens? (a) may burn out (b) lights up (c) does not light
20. 20.🔺 A current of 2 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
21. 21.🔺 A current of 40 mA flows through a 300 Ω resistor. What is the voltage across it (in volts)? =
22. 22.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
23. 23.🧾 A 100 W filament bulb is swapped for a 15 W LED lamp that gives about the same light. Both would run for 1 hour. How many watt-hours (Wh) are saved?
24. 24.🧮 A 2.5 V battery is joined to 2 Ω and 3 Ω resistors in series. What current flows (in amperes)? =
25. 25.🧮 Three equal 150 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
26. 26.True or false: voltage is measured in volts (V). (a) False (b) True
27. 27.💡 A red LED (it uses 2 V) is joined with a 100 Ω resistor to a 3 V supply. What current flows (in mA)?
28. 28.🔺 A current of 20 mA flows through a 250 Ω resistor. What is the voltage across it (in volts)? =
29. 29.🔺 A 0.5 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =
30. 30.🔺 A 2 V supply is joined across a 200 Ω resistor. What current flows (in milliamperes, mA)?
31. 31.📏 How many milliamperes (mA) is 2.5 A?
32. 32.⚡ A device works on 9 V and takes 1.5 A. What is its power (in watts)? =
33. 33.⚡ A 0.9 W device works on 9 V. What current does it take (in amperes)? =
34. 34.🌈 Which band is read first on a resistor? (a) any band (b) the widest gap (c) the gold band (d) the one nearest an end
35. 35.🌈 A resistor has the colour bands blue, blue, black. What is its value (in ohms)?
36. 36.🧾 A 200 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
37. 37.⚡ A home appliance on the 230 V mains takes 5 A. What is its power (in watts)?
38. 38.True or false: on an LED, the longer leg is the cathode (−). (a) True (b) False
39. 39.📏 Which unit measures how much a part resists? (a) volt (V) (b) ampere (A) (c) watt (W) (d) ohm (Ω)
40. 40.🔺 A current of 25 mA flows when 6.25 V is joined across a resistor. What is its resistance (in ohms)?

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