Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 493 · 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 home appliance on the 230 V mains takes 1 A. What is its power (in watts)?
2. 2.🧮 A 330 Ω resistor is joined in series with two equal 1000 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
3. 3.⚡ Power tells us … (a) the colour of light (b) energy used each second (c) the length of a wire (d) the size of a cell
4. 4.True or false: power is measured in watts (W). (a) False (b) True
5. 5.True or false: the voltmeter measures current. (a) False (b) True
6. 6.🧮 Resistors of 20 Ω and 150 Ω are joined in series. What is the total resistance (in ohms)?
7. 7.Which of these is measured in volts (V)? (a) how much a part resists (b) energy used each second (c) the flow of charge (d) the push of a cell
8. 8.🌈 A resistor has the colour bands yellow, green, orange. What is its value in kilo-ohms (kΩ)? =
9. 9.True or false: a buzzer makes a beeping sound. (a) True (b) False
10. 10.🔺 A current of 0.2 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
11. 11.🔺 A current of 3 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
12. 12.Which of these wastes electricity? (a) switch off empty rooms (b) use old filament bulbs (c) use LED lamps (d) set the AC to 24 °C
13. 13.Which of these saves electricity? (a) close the fridge quickly (b) leave fridge door open (c) use old filament bulbs (d) iron one shirt at a time
14. 14.🔺 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
15. 15.🔺 A current of 2 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
16. 16.🔺 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
17. 17.🌈 A resistor has the colour bands violet, white, red. What is its value (in ohms)?
18. 18.🔺 A current of 2.5 A flows when 37.5 V is joined across a resistor. What is its resistance (in ohms)?
19. 19.⚡ A 2.4 W device works on 12 V. What current does it take (in amperes)? =
20. 20.🔺 A 15 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =
21. 21.🔺 In the V-I-R triangle, how do we find V? (a) V = I + R (b) V = R ÷ I (c) V = I ÷ R (d) V = I × R
22. 22.💡 A red LED (it uses 2 V) is joined with a 150 Ω resistor to a 5 V supply. What current flows (in mA)?
23. 23.True or false: the voltmeter is joined across a part. (a) True (b) False
24. 24.🌈 A gold fourth band on a resistor means the value may be off by … (a) 5 % (b) 0 % (c) 25 % (d) 50 %
25. 25.🧮 Two resistors in parallel give a total that is … (a) less than either one (b) their sum (c) more than either one (d) always zero
26. 26.🔺 A 3 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
27. 27.🧾 A family uses 120 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
28. 28.What does a buzzer do? (a) beeps for an alarm (b) senses how bright it is (c) senses how hot it is (d) is a resistance knob
29. 29.🧩 Which component glows using little power? (a) motor (b) LED (c) potentiometer (d) buzzer
30. 30.🌈 A resistor has the colour bands red, white, brown. What is its value (in ohms)?
31. 31.⚡ A device works on 9 V and takes 3 A. What is its power (in watts)? =
32. 32.🧮 Adding another resistor in series makes the total resistance … (a) bigger (b) zero (c) smaller (d) stay the same
33. 33.⚡ A device works on 24 V and takes 0.5 A. What is its power (in watts)? =
34. 34.⚡ Which formula gives electric power? (a) P = V + I (b) P = V ÷ I (c) P = V × I (d) P = I ÷ V
35. 35.🧮 A 33 Ω resistor is joined in series with two equal 330 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
36. 36.💡 A red LED (it uses 2 V) is joined with a 200 Ω resistor to a 4 V supply. What current flows (in mA)?
37. 37.🧩 Which part changes electrical energy into movement? (a) an LED (b) a fuse (c) a motor (d) a resistor
38. 38.💡 Does it save or waste electricity to switch off empty rooms? (a) wastes electricity (b) saves electricity
39. 39.⚡ A home appliance on the 230 V mains takes 1.5 A. What is its power (in watts)?
40. 40.True or false: the voltmeter measures voltage. (a) False (b) True

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