Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 942 · 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.🧮 Two resistors in parallel give a total that is … (a) their sum (b) more than either one (c) always zero (d) less than either one
2. 2.🔺 A current of 0.2 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
3. 3.⚡ Power tells us … (a) the size of a cell (b) the length of a wire (c) energy used each second (d) the colour of light
4. 4.💡 A blue LED uses 3 V and should get 10 mA. It runs from a 5 V supply. What resistor (in ohms) is needed in series?
5. 5.🔺 A 12 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
6. 6.🔺 A current of 20 mA flows when 2.4 V is joined across a resistor. What is its resistance (in ohms)?
7. 7.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V × I (c) P = V ÷ I (d) P = V + I
8. 8.📏 In the water-pipe picture of a circuit, resistance is like … (a) a bigger tank (b) the water pressure (c) a narrow pipe (d) the flow of water
9. 9.🔺 A current of 10 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
10. 10.⚡ A device works on 12 V and takes 0.1 A. What is its power (in watts)? =
11. 11.🔺 A current of 20 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
12. 12.📏 How many amperes (A) is 100 mA? =
13. 13.🌈 In the resistor colour code, which number does orange stand for?
14. 14.Which of these saves electricity? (a) leave the TV on standby (b) iron one shirt at a time (c) use old filament bulbs (d) unplug idle chargers
15. 15.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
16. 16.⚡ A 24 W device works on 24 V. What current does it take (in amperes)? =
17. 17.🔺 A current of 1 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
18. 18.🔍 Which is the odd one out? (a) use daylight to read (b) unplug idle chargers (c) switch off empty rooms (d) iron one shirt at a time
19. 19.🌈 In the resistor colour code, which number does yellow stand for?
20. 20.🧩 Which component smooths a wobbly supply? (a) buzzer (b) LDR (c) capacitor (d) motor
21. 21.🔺 A 10 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
22. 22.🧮 Two equal 330 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
23. 23.🌈 A resistor has the colour bands blue, orange, red. What is its value (in ohms)?
24. 24.🔺 In the V-I-R triangle, how do we find V? (a) V = I × R (b) V = I + R (c) V = R ÷ I (d) V = I ÷ R
25. 25.🧩 Which component glows using little power? (a) LED (b) potentiometer (c) thermistor (d) motor
26. 26.🌈 A resistor has the colour bands yellow, green, orange. What is its value (in ohms)?
27. 27.🌈 A resistor has the colour bands brown, brown, brown. What is its value (in ohms)?
28. 28.What does a potentiometer do? (a) turns a fan or wheels (b) makes a beeping sound (c) is a resistance knob (d) smooths a wobbly supply
29. 29.🧾 A family uses 190 units of electricity in a month and each unit costs ₹5. What is the bill (in ₹)?
30. 30.🔺 A current of 3 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
31. 31.📏 How many watts (W) is 1.3 kW?
32. 32.💡 A red LED (it uses 2 V) is joined with a 300 Ω resistor to a 5 V supply. What current flows (in mA)?
33. 33.🔍 Which is the odd one out? (a) use daylight to read (b) use old filament bulbs (c) leave the TV on standby (d) iron one shirt at a time
34. 34.🌈 Which band is read first on a resistor? (a) the gold band (b) any band (c) the one nearest an end (d) the widest gap
35. 35.🔺 A current of 0.5 A flows when 5 V is joined across a resistor. What is its resistance (in ohms)?
36. 36.🧩 Which component makes things spin? (a) resistor (b) buzzer (c) potentiometer (d) motor
37. 37.📏 How many amperes (A) is 2170 mA? =
38. 38.🧾 A 1500 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =
39. 39.💡 A red LED (it uses 2 V) is joined with a 150 Ω resistor to a 3.5 V supply. What current flows (in mA)?
40. 40.🧮 Resistors of 10 Ω, 150 Ω and 330 Ω are joined in series. What is the total resistance (in ohms)?

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