Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 613 · 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 20 Ω resistor is joined in series with two equal 220 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
2. 2.📏 How many amperes (A) is 1420 mA? =
3. 3.🧾 A 200 W appliance runs for 6 hours. How many units (kWh) of electricity does it use? =
4. 4.🧮 Two resistors in parallel give a total that is … (a) less than either one (b) more than either one (c) always zero (d) their sum
5. 5.📏 In the water-pipe picture of a circuit, resistance is like … (a) the water pressure (b) the flow of water (c) a narrow pipe (d) a bigger tank
6. 6.💡 Why does an LED need a resistor in series? (a) to make it brighter (b) to limit the current (c) to store charge (d) to change its colour
7. 7.🔺 A current of 2 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
8. 8.⚡ Which formula gives electric power? (a) P = V ÷ I (b) P = V + I (c) P = I ÷ V (d) P = V × I
9. 9.🧩 Which component glows using little power? (a) LED (b) capacitor (c) buzzer (d) diode
10. 10.🧩 Which component is a resistance knob? (a) LED (b) buzzer (c) potentiometer (d) thermistor
11. 11.⚡ A device works on 12 V and takes 1.5 A. What is its power (in watts)? =
12. 12.⚡ A home appliance on the 230 V mains takes 2 A. What is its power (in watts)?
13. 13.🔺 A 15 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =
14. 14.🧾 A 100 W appliance runs for 10 hours. How many units (kWh) of electricity does it use? =
15. 15.⚡ A home appliance on the 230 V mains takes 10 A. What is its power (in watts)?
16. 16.🧾 A family uses 180 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
17. 17.🔺 A 45 V supply is joined across a 15 Ω resistor. What current flows (in amperes)? =
18. 18.🔍 Which is the odd one out? (a) unplug idle chargers (b) close the fridge quickly (c) use old filament bulbs (d) set the AC to 24 °C
19. 19.🧮 Adding another resistor in series makes the total resistance … (a) stay the same (b) zero (c) smaller (d) bigger
20. 20.Which of these is measured in volts (V)? (a) power (b) voltage (c) energy used each second (d) current
21. 21.💡 What happens if an LED is put in backwards? (a) it changes colour (b) it makes a sound (c) it lights brighter (d) it does not light
22. 22.Which of these wastes electricity? (a) use LED lamps (b) switch off empty rooms (c) iron one shirt at a time (d) set the AC to 24 °C
23. 23.🔺 A current of 0.25 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
24. 24.📏 Voltmeter or ammeter: which one is joined in series? (a) voltmeter (b) ammeter
25. 25.🧾 A family uses 150 units of electricity in a month and each unit costs ₹6. What is the bill (in ₹)?
26. 26.📏 How many amperes (A) is 2020 mA? =
27. 27.Which of these saves electricity? (a) run fans in empty rooms (b) use LED lamps (c) iron one shirt at a time (d) use old filament bulbs
28. 28.🔺 A current of 20 mA flows when 4 V is joined across a resistor. What is its resistance (in ohms)?
29. 29.🧮 A 3 V battery is joined to 4 Ω and 8 Ω resistors in series. What current flows (in amperes)? =
30. 30.🔺 In the V-I-R triangle, how do we find R? (a) R = I ÷ V (b) R = V + I (c) R = V × I (d) R = V ÷ I
31. 31.🧩 Which component turns a fan or wheels? (a) LED (b) resistor (c) motor (d) fuse
32. 32.True or false: to use daylight to read saves electricity. (a) False (b) True
33. 33.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 580 Ω resistor? (a) green-grey-brown (b) grey-green-brown (c) green-grey-red (d) green-grey-black
34. 34.🔺 In the V-I-R triangle, how do we find I? (a) I = R ÷ V (b) I = V ÷ R (c) I = V × R (d) I = V + R
35. 35.🧮 Two equal 200 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
36. 36.🧩 Which part changes electrical energy into sound? (a) a capacitor (b) a buzzer (c) a resistor (d) a diode
37. 37.⚡ A home appliance on the 230 V mains takes 1 A. What is its power (in watts)?
38. 38.🔺 A current of 1.5 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
39. 39.🔍 Which is the odd one out? (a) iron one shirt at a time (b) use old filament bulbs (c) run fans in empty rooms (d) use LED lamps
40. 40.🧮 A 33 Ω resistor is joined in series with two equal 470 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?

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