Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 212 · 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.True or false: the ammeter is joined across a part. (a) True (b) False
2. 2.🔺 In the V-I-R triangle, how do we find I? (a) I = V × R (b) I = V ÷ R (c) I = R ÷ V (d) I = V + R
3. 3.💡 What does LED stand for? (a) low energy device (b) large electric dial (c) light-emitting diode (d) light energy dial
4. 4.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 58000 Ω resistor? (a) green-grey-red (b) green-grey-yellow (c) green-grey-orange (d) grey-green-orange
5. 5.🧩 A capacitor in a circuit can … (a) store charge briefly (b) make light (c) measure heat (d) spin a wheel
6. 6.💡 A blue LED uses 3 V and should get 20 mA. It runs from a 12 V supply. What resistor (in ohms) is needed in series?
7. 7.True or false: the flow of charge is measured in amperes (A). (a) True (b) False
8. 8.True or false: the flow of charge is measured in volts (V). (a) False (b) True
9. 9.🔺 A current of 2 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
10. 10.🔺 A 6.6 V supply is joined across a 330 Ω resistor. What current flows (in milliamperes, mA)?
11. 11.🔍 Which is the odd one out? (a) unplug idle chargers (b) run fans in empty rooms (c) switch off empty rooms (d) close the fridge quickly
12. 12.What does a motor do? (a) stores a little charge (b) senses how hot it is (c) limits the current (d) makes things spin
13. 13.🔺 A current of 40 mA flows when 6 V is joined across a resistor. What is its resistance (in ohms)?
14. 14.True or false: to leave the TV on standby wastes electricity. (a) True (b) False
15. 15.🧾 A 200 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =
16. 16.🌈 A resistor has the colour bands green, brown, yellow. What is its value in kilo-ohms (kΩ)? =
17. 17.🧮 Five equal 500 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
18. 18.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets bigger (b) gets smaller (c) stays the same (d) becomes zero
19. 19.🌈 A resistor has the colour bands blue, red, red. What is its value in kilo-ohms (kΩ)? =
20. 20.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
21. 21.🔺 A current of 1.5 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
22. 22.🔺 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
23. 23.🔍 Which is the odd one out? (a) leave fridge door open (b) leave the TV on standby (c) iron one shirt at a time (d) use LED lamps
24. 24.⚡ Power tells us … (a) the size of a cell (b) the colour of light (c) the length of a wire (d) energy used each second
25. 25.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
26. 26.🧮 Resistors of 50 Ω, 22 Ω, 33 Ω and 150 Ω are joined in series. What is the total resistance (in ohms)?
27. 27.💡 An LED is joined to a 3 V battery through a 220 Ω resistor; its long leg goes to the + side and its short leg to the − side. What happens? (a) may burn out (b) does not light (c) lights up
28. 28.Which of these is measured in amperes (A)? (a) power (b) how much a part resists (c) current (d) energy used each second
29. 29.🔺 A current of 50 mA flows when 23.5 V is joined across a resistor. What is its resistance (in ohms)?
30. 30.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
31. 31.🔺 A current of 20 mA flows when 4 V is joined across a resistor. What is its resistance (in ohms)?
32. 32.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 39 Ω resistor? (a) orange-white-black (b) orange-white-brown (c) white-orange-black (d) yellow-white-black
33. 33.True or false: to run fans in empty rooms saves electricity. (a) False (b) True
34. 34.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 160 Ω resistor? (a) brown-blue-red (b) brown-blue-black (c) blue-brown-brown (d) brown-blue-brown
35. 35.🌈 A resistor has the colour bands orange, orange, yellow. What is its value in kilo-ohms (kΩ)? =
36. 36.True or false: an LED makes a beeping sound. (a) True (b) False
37. 37.🧮 Two equal 10 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
38. 38.True or false: on an LED, the longer leg is the anode (+). (a) True (b) False
39. 39.🔺 A current of 20 mA flows through a 120 Ω resistor. What is the voltage across it (in volts)? =
40. 40.🔺 A 20 V supply is joined across a 400 Ω resistor. What current flows (in milliamperes, mA)?

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