Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 851 · 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 6 W device works on 12 V. What current does it take (in amperes)? =
2. 2.🔺 A current of 10 mA flows through a 250 Ω resistor. What is the voltage across it (in volts)? =
3. 3.Which of these is measured in watts (W)? (a) current (b) the push of a cell (c) how much a part resists (d) energy used each second
4. 4.🔺 A current of 50 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
5. 5.True or false: to leave the TV on standby wastes electricity. (a) False (b) True
6. 6.🧩 Which component boosts a small signal? (a) transistor (b) thermistor (c) capacitor (d) LDR
7. 7.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets bigger (b) stays the same (c) gets smaller (d) becomes zero
8. 8.⚡ Which formula gives electric power? (a) P = V × I (b) P = V + I (c) P = V ÷ I (d) P = I ÷ V
9. 9.🌈 Which band is read first on a resistor? (a) the gold band (b) the widest gap (c) the one nearest an end (d) any band
10. 10.🧩 A capacitor in a circuit can … (a) measure heat (b) make light (c) store charge briefly (d) spin a wheel
11. 11.True or false: resistance is measured in amperes (A). (a) True (b) False
12. 12.True or false: the voltmeter is joined in series. (a) False (b) True
13. 13.🌈 A resistor has the colour bands violet, black, black. What is its value (in ohms)?
14. 14.🧮 Two equal 40 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
15. 15.Which of these is measured in amperes (A)? (a) power (b) energy used each second (c) how much a part resists (d) the flow of charge
16. 16.🧮 Resistors of 20 Ω, 10 Ω, 10 Ω and 50 Ω are joined in series. What is the total resistance (in ohms)?
17. 17.💡 An LED is joined to a 3 V battery through a 330 Ω resistor; its long leg goes to the − side and its short leg to the + side. What happens? (a) does not light (b) may burn out (c) lights up
18. 18.🧮 Resistors of 330 Ω and 150 Ω are joined in series. What is the total resistance (in ohms)?
19. 19.🧮 Two equal 50 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
20. 20.📏 How many milliamperes (mA) is 1.53 A?
21. 21.🧮 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
22. 22.🧮 Resistors of 330 Ω and 220 Ω are joined in series. What is the total resistance (in ohms)?
23. 23.🧾 A 200 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
24. 24.True or false: a resistor makes a beeping sound. (a) False (b) True
25. 25.🔍 Which is the odd one out? (a) unplug idle chargers (b) run fans in empty rooms (c) close the fridge quickly (d) set the AC to 24 °C
26. 26.🧩 Which part changes electrical energy into sound? (a) a resistor (b) a diode (c) a buzzer (d) a capacitor
27. 27.⚡ A 13.5 W device works on 9 V. What current does it take (in amperes)? =
28. 28.🔺 A 2.4 V supply is joined across a 12 Ω resistor. What current flows (in amperes)? =
29. 29.🧮 Five equal 25 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
30. 30.True or false: a fuse stores a little charge. (a) True (b) False
31. 31.Which of these is measured in amperes (A)? (a) resistance (b) current (c) how much a part resists (d) power
32. 32.🧩 Which component glows using little power? (a) motor (b) transistor (c) potentiometer (d) LED
33. 33.📏 How many kilowatts (kW) is 3450 W? =
34. 34.🔺 A current of 0.2 A flows when 2 V is joined across a resistor. What is its resistance (in ohms)?
35. 35.True or false: on an LED, the leg by the flat edge is the cathode (−). (a) True (b) False
36. 36.💡 A red LED uses 2 V and should get 10 mA. It runs from a 9 V supply. What resistor (in ohms) is needed in series?
37. 37.🌈 A resistor has the colour bands red, white, black. What is its value (in ohms)?
38. 38.🔺 A current of 10 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
39. 39.🌈 In the resistor colour code, which number does green stand for?
40. 40.⚡ A device works on 12 V and takes 0.2 A. What is its power (in watts)? =

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