Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 959 · 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 capacitor in a circuit can … (a) measure heat (b) store charge briefly (c) make light (d) spin a wheel
2. 2.🧮 Three equal 150 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
3. 3.🔺 A current of 50 mA flows when 10 V is joined across a resistor. What is its resistance (in ohms)?
4. 4.🧮 Resistors of 330 Ω and 330 Ω are joined in series. What is the total resistance (in ohms)?
5. 5.💡 An LED is joined to a 3 V battery through a 330 Ω resistor; the leg next to the flat edge of its rim goes to the + side. What happens? (a) lights up (b) may burn out (c) does not light
6. 6.💡 An LED is joined to a 5 V battery through a 470 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
7. 7.🔍 Which is the odd one out? (a) iron one shirt at a time (b) leave the TV on standby (c) leave fridge door open (d) use daylight to read
8. 8.True or false: the ammeter measures current. (a) True (b) False
9. 9.🔺 A current of 1 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
10. 10.🧮 Two equal 220 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
11. 11.🌈 Which band is read first on a resistor? (a) the gold band (b) the widest gap (c) any band (d) the one nearest an end
12. 12.True or false: the voltmeter is joined across a part. (a) False (b) True
13. 13.🧾 A 40 W filament bulb is swapped for a 6 W LED lamp that gives about the same light. Both would run for 3 hours. How many watt-hours (Wh) are saved?
14. 14.📏 Which unit measures the push of a cell? (a) watt (W) (b) volt (V) (c) ampere (A) (d) ohm (Ω)
15. 15.🔺 A current of 3 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
16. 16.Which of these is measured in ohms (Ω)? (a) the push of a cell (b) how much a part resists (c) power (d) voltage
17. 17.⚡ Which formula gives electric power? (a) P = V ÷ I (b) P = V + I (c) P = I ÷ V (d) P = V × I
18. 18.📏 Which unit measures how much a part resists? (a) ampere (A) (b) watt (W) (c) ohm (Ω) (d) volt (V)
19. 19.True or false: to run fans in empty rooms wastes electricity. (a) True (b) False
20. 20.True or false: a diode lets current go one way. (a) True (b) False
21. 21.🌈 A resistor has the colour bands blue, orange, orange. What is its value (in ohms)?
22. 22.🧮 Resistors of 20 Ω and 33 Ω are joined in series. What is the total resistance (in ohms)?
23. 23.📏 Voltmeter or ammeter: which one measures voltage? (a) voltmeter (b) ammeter
24. 24.🧩 Which component has coloured bands? (a) resistor (b) potentiometer (c) diode (d) motor
25. 25.🌈 A resistor has the colour bands grey, blue, orange. What is its value (in ohms)?
26. 26.⚡ Power tells us … (a) the length of a wire (b) the colour of light (c) the size of a cell (d) energy used each second
27. 27.🔺 In the V-I-R triangle, how do we find I? (a) I = V ÷ R (b) I = V × R (c) I = V + R (d) I = R ÷ V
28. 28.🌈 In the resistor colour code, which number does green stand for?
29. 29.🔺 A current of 40 mA flows when 10 V is joined across a resistor. What is its resistance (in ohms)?
30. 30.🧮 Two equal 1000 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
31. 31.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
32. 32.True or false: to leave fridge door open saves electricity. (a) True (b) False
33. 33.🔺 A current of 10 mA flows when 2.2 V is joined across a resistor. What is its resistance (in ohms)?
34. 34.🔺 A current of 2.5 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
35. 35.🔺 A current of 40 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
36. 36.📏 How many kilo-ohms (kΩ) is 4600 Ω? =
37. 37.True or false: a capacitor stores a little charge. (a) False (b) True
38. 38.📏 Voltmeter or ammeter: which one is joined in series? (a) voltmeter (b) ammeter
39. 39.💡 A red LED (it uses 2 V) is joined with a 100 Ω resistor to a 3 V supply. What current flows (in mA)?
40. 40.Which of these is measured in volts (V)? (a) resistance (b) voltage (c) power (d) the flow of charge

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