Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 670 · 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 1.3 V battery is joined to 8 Ω and 5 Ω resistors in series. What current flows (in amperes)? =
2. 2.📏 Voltmeter or ammeter: which one measures voltage? (a) ammeter (b) voltmeter
3. 3.🔺 A current of 0.1 A flows when 0.6 V is joined across a resistor. What is its resistance (in ohms)?
4. 4.🌈 A gold fourth band on a resistor means the value may be off by … (a) 0 % (b) 50 % (c) 5 % (d) 25 %
5. 5.True or false: a capacitor senses how hot it is. (a) True (b) False
6. 6.🔺 A current of 50 mA flows through a 120 Ω resistor. What is the voltage across it (in volts)? =
7. 7.🧮 A 4 V battery is joined to 2 Ω and 2 Ω resistors in series. What current flows (in amperes)? =
8. 8.🔺 A current of 2.5 A flows when 20 V is joined across a resistor. What is its resistance (in ohms)?
9. 9.🧩 Which part changes electrical energy into sound? (a) a buzzer (b) a diode (c) a capacitor (d) a resistor
10. 10.🧾 A family uses 60 units of electricity in a month and each unit costs ₹8. What is the bill (in ₹)?
11. 11.🔺 A current of 50 mA flows through a 500 Ω resistor. What is the voltage across it (in volts)? =
12. 12.⚡ A 72 W device works on 24 V. What current does it take (in amperes)? =
13. 13.🧮 Two equal 20 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
14. 14.True or false: a capacitor boosts a small signal. (a) True (b) False
15. 15.🌈 A resistor has the colour bands blue, brown, yellow. What is its value in kilo-ohms (kΩ)? =
16. 16.Which of these wastes electricity? (a) use daylight to read (b) use LED lamps (c) use old filament bulbs (d) close the fridge quickly
17. 17.💡 A red LED (it uses 2 V) is joined with a 300 Ω resistor to a 3.5 V supply. What current flows (in mA)?
18. 18.True or false: the voltmeter measures current. (a) True (b) False
19. 19.🔺 A current of 2 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
20. 20.💡 An LED is joined to a 9 V battery through a 330 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
21. 21.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
22. 22.🌈 In the resistor colour code, which number does red stand for?
23. 23.🧾 Which lamp gives the same light for the least power? (a) a filament bulb (b) a candle (c) an LED lamp (d) an oil lamp
24. 24.🔺 A current of 50 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
25. 25.🧩 Which component is a resistance knob? (a) LED (b) potentiometer (c) diode (d) capacitor
26. 26.What does a thermistor do? (a) glows using little power (b) limits the current (c) lets current go one way (d) senses how hot it is
27. 27.🧩 Which component beeps for an alarm? (a) buzzer (b) potentiometer (c) diode (d) motor
28. 28.🌈 Which band is read first on a resistor? (a) the widest gap (b) any band (c) the one nearest an end (d) the gold band
29. 29.📏 Voltmeter or ammeter: which one measures current? (a) voltmeter (b) ammeter
30. 30.🧾 A family uses 80 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
31. 31.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
32. 32.🔺 A current of 50 mA flows when 11 V is joined across a resistor. What is its resistance (in ohms)?
33. 33.🔺 A current of 10 mA flows when 3.3 V is joined across a resistor. What is its resistance (in ohms)?
34. 34.⚡ A device works on 3 V and takes 3 A. What is its power (in watts)? =
35. 35.📏 In the water-pipe picture of a circuit, resistance is like … (a) a narrow pipe (b) the flow of water (c) a bigger tank (d) the water pressure
36. 36.What does a capacitor do? (a) limits the current (b) glows using little power (c) stores a little charge (d) has coloured bands
37. 37.🔺 A current of 20 mA flows when 6 V is joined across a resistor. What is its resistance (in ohms)?
38. 38.🔺 A current of 2 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
39. 39.💡 A red LED (it uses 2 V) is joined with a 150 Ω resistor to a 2.75 V supply. What current flows (in mA)?
40. 40.🔺 A 3.75 V supply is joined across a 150 Ω resistor. What current flows (in milliamperes, mA)?

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