Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 221 · 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 1.2 V supply is joined across a 12 Ω resistor. What current flows (in amperes)? =
2. 2.🌈 In the resistor colour code, which number does orange stand for?
3. 3.⚡ A home appliance on the 230 V mains takes 4 A. What is its power (in watts)?
4. 4.🔺 A current of 20 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
5. 5.🌈 Which band is read first on a resistor? (a) the one nearest an end (b) the gold band (c) the widest gap (d) any band
6. 6.🔺 A current of 40 mA flows when 18.8 V is joined across a resistor. What is its resistance (in ohms)?
7. 7.Which of these is measured in watts (W)? (a) how much a part resists (b) energy used each second (c) the push of a cell (d) resistance
8. 8.🧮 Five equal 125 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
9. 9.🔺 A 3 V supply is joined across a 150 Ω resistor. What current flows (in milliamperes, mA)?
10. 10.🧩 Which part changes electrical energy into movement? (a) an LED (b) a fuse (c) a resistor (d) a motor
11. 11.💡 A red LED (it uses 2 V) is joined with a 100 Ω resistor to a 3 V supply. What current flows (in mA)?
12. 12.🧩 A capacitor in a circuit can … (a) make light (b) measure heat (c) spin a wheel (d) store charge briefly
13. 13.🧮 A 9 V battery is joined to 6 Ω and 3 Ω resistors in series. What current flows (in amperes)? =
14. 14.What does a capacitor do? (a) blows if current is high (b) makes things spin (c) makes a beeping sound (d) stores a little charge
15. 15.🔺 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
16. 16.True or false: the ammeter measures current. (a) False (b) True
17. 17.⚡ A device works on 9 V and takes 0.2 A. What is its power (in watts)? =
18. 18.🔍 Which is the odd one out? (a) use daylight to read (b) unplug idle chargers (c) switch off empty rooms (d) run fans in empty rooms
19. 19.🧾 A family uses 60 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
20. 20.🌈 A resistor has the colour bands violet, violet, black. What is its value (in ohms)?
21. 21.Which of these is measured in volts (V)? (a) current (b) energy used each second (c) the push of a cell (d) power
22. 22.🔺 A current of 0.2 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
23. 23.🔺 A current of 20 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
24. 24.📏 Which unit measures resistance? (a) volt (V) (b) ampere (A) (c) watt (W) (d) ohm (Ω)
25. 25.🔺 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
26. 26.🔺 A current of 1.5 A flows when 3 V is joined across a resistor. What is its resistance (in ohms)?
27. 27.🧩 Which part changes electrical energy into sound? (a) a buzzer (b) a diode (c) a resistor (d) a capacitor
28. 28.🧾 Which lamp gives the same light for the least power? (a) a filament bulb (b) an oil lamp (c) a candle (d) an LED lamp
29. 29.🔺 A current of 25 mA flows through a 250 Ω resistor. What is the voltage across it (in volts)? =
30. 30.🔺 A current of 25 mA flows when 7.5 V is joined across a resistor. What is its resistance (in ohms)?
31. 31.📏 How many ohms make 1 kilo-ohm (kΩ)? (a) 10 (b) 1000 (c) 1024 (d) 100
32. 32.🔺 A current of 0.2 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
33. 33.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
34. 34.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
35. 35.🔺 A 2 V supply is joined across a 200 Ω resistor. What current flows (in milliamperes, mA)?
36. 36.🧾 A 100 W appliance runs for 8 hours. How many units (kWh) of electricity does it use? =
37. 37.📏 Voltmeter or ammeter: which one measures voltage? (a) ammeter (b) voltmeter
38. 38.🌈 In the resistor colour code, which number does grey stand for?
39. 39.🔺 A current of 10 mA flows through a 500 Ω resistor. What is the voltage across it (in volts)? =
40. 40.⚡ A device works on 1.5 V and takes 0.1 A. What is its power (in watts)? =

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