Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 234 · 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 amperes (A) is 1010 mA? =
2. 2.🌈 A resistor has the colour bands violet, yellow, brown. What is its value (in ohms)?
3. 3.🧮 Resistors of 10 Ω, 50 Ω, 100 Ω and 330 Ω are joined in series. What is the total resistance (in ohms)?
4. 4.📏 Which unit measures the push of a cell? (a) watt (W) (b) ampere (A) (c) ohm (Ω) (d) volt (V)
5. 5.💡 Why does an LED need a resistor in series? (a) to store charge (b) to make it brighter (c) to change its colour (d) to limit the current
6. 6.🔺 A current of 50 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
7. 7.🔺 A current of 0.2 A flows when 2 V is joined across a resistor. What is its resistance (in ohms)?
8. 8.📏 How many ohms make 1 kilo-ohm (kΩ)? (a) 1000 (b) 1024 (c) 100 (d) 10
9. 9.🧮 Two equal 10 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
10. 10.🔺 A current of 0.25 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
11. 11.🔺 A current of 40 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
12. 12.🧩 Which component blows if current is high? (a) capacitor (b) resistor (c) potentiometer (d) fuse
13. 13.True or false: the flow of charge is measured in watts (W). (a) False (b) True
14. 14.💡 What happens if an LED is put in backwards? (a) it makes a sound (b) it changes colour (c) it lights brighter (d) it does not light
15. 15.🧮 Two resistors in parallel give a total that is … (a) always zero (b) more than either one (c) their sum (d) less than either one
16. 16.⚡ Power tells us … (a) the size of a cell (b) the colour of light (c) energy used each second (d) the length of a wire
17. 17.🔺 In the V-I-R triangle, how do we find R? (a) R = V + I (b) R = V × I (c) R = V ÷ I (d) R = I ÷ V
18. 18.True or false: the push of a cell is measured in amperes (A). (a) True (b) False
19. 19.🧩 Which part changes electrical energy into sound? (a) a capacitor (b) a diode (c) a resistor (d) a buzzer
20. 20.🔺 A current of 50 mA flows through a 470 Ω resistor. What is the voltage across it (in volts)? =
21. 21.🧮 Adding another resistor in series makes the total resistance … (a) smaller (b) zero (c) stay the same (d) bigger
22. 22.True or false: to close the fridge quickly saves electricity. (a) True (b) False
23. 23.🌈 A resistor has the colour bands white, orange, brown. What is its value (in ohms)?
24. 24.🌈 A resistor has the colour bands blue, brown, red. What is its value (in ohms)?
25. 25.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) stays the same (b) becomes zero (c) gets bigger (d) gets smaller
26. 26.🧮 A 1.2 V battery is joined to 2 Ω and 4 Ω resistors in series. What current flows (in amperes)? =
27. 27.🔺 A 2 V supply is joined across a 100 Ω resistor. What current flows (in milliamperes, mA)?
28. 28.🧾 A 100 W appliance runs for 6 hours. How many units (kWh) of electricity does it use? =
29. 29.🔺 A 2 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
30. 30.💡 Does it save or waste electricity to leave fridge door open? (a) wastes electricity (b) saves electricity
31. 31.🧮 A 3.25 V battery is joined to 10 Ω and 3 Ω resistors in series. What current flows (in amperes)? =
32. 32.True or false: on an LED, the longer leg is the cathode (−). (a) True (b) False
33. 33.🔺 A current of 0.5 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
34. 34.📏 How many watts (W) is 1.6 kW?
35. 35.💡 Does it save or waste electricity to use LED lamps? (a) wastes electricity (b) saves electricity
36. 36.🔺 A current of 2.5 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
37. 37.🔺 A current of 20 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
38. 38.🔺 An 11.75 V supply is joined across a 470 Ω resistor. What current flows (in milliamperes, mA)?
39. 39.🌈 A resistor has the colour bands orange, red, brown. What is its value (in ohms)?
40. 40.🔺 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

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