Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 357 · 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.🔺 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
2. 2.🔺 A current of 1.5 A flows when 9 V is joined across a resistor. What is its resistance (in ohms)?
3. 3.🧮 A 330 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)?
4. 4.⚡ A 1.5 W device works on 3 V. What current does it take (in amperes)? =
5. 5.🔍 Which is the odd one out? (a) run fans in empty rooms (b) leave the TV on standby (c) use old filament bulbs (d) unplug idle chargers
6. 6.⚡ A 6 W device works on 3 V. What current does it take (in amperes)? =
7. 7.⚡ A home appliance on the 230 V mains takes 0.5 A. What is its power (in watts)?
8. 8.Which of these wastes electricity? (a) leave the TV on standby (b) set the AC to 24 °C (c) use daylight to read (d) switch off empty rooms
9. 9.True or false: on an LED, the round-side leg is the anode (+). (a) True (b) False
10. 10.🔺 A 6 V supply is joined across a 120 Ω resistor. What current flows (in milliamperes, mA)?
11. 11.🧮 Two resistors in parallel give a total that is … (a) more than either one (b) their sum (c) always zero (d) less than either one
12. 12.⚡ Which formula gives electric power? (a) P = V × I (b) P = V + I (c) P = V ÷ I (d) P = I ÷ V
13. 13.⚡ A device works on 6 V and takes 0.5 A. What is its power (in watts)? =
14. 14.🧾 A family uses 190 units of electricity in a month and each unit costs ₹7. What is the bill (in ₹)?
15. 15.🔺 A 0.4 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
16. 16.🧩 Which component boosts a small signal? (a) motor (b) potentiometer (c) capacitor (d) transistor
17. 17.🔺 In the V-I-R triangle, how do we find V? (a) V = I ÷ R (b) V = I + R (c) V = R ÷ I (d) V = I × R
18. 18.📏 How many milliamperes (mA) make 1 ampere? (a) 100 (b) 60 (c) 10 (d) 1000
19. 19.⚡ Power tells us … (a) the colour of light (b) the size of a cell (c) the length of a wire (d) energy used each second
20. 20.🔍 Which is the odd one out? (a) leave fridge door open (b) iron one shirt at a time (c) switch off empty rooms (d) use old filament bulbs
21. 21.🧮 Resistors of 33 Ω, 150 Ω, 47 Ω and 22 Ω are joined in series. What is the total resistance (in ohms)?
22. 22.🧮 Adding another resistor in series makes the total resistance … (a) smaller (b) zero (c) bigger (d) stay the same
23. 23.🧮 Three equal 75 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
24. 24.💡 An LED is joined to a 5 V battery through a 330 Ω resistor; the leg next to the flat edge of its rim goes to the − side. What happens? (a) does not light (b) lights up (c) may burn out
25. 25.💡 Does it save or waste electricity to use old filament bulbs? (a) wastes electricity (b) saves electricity
26. 26.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
27. 27.True or false: on an LED, the longer leg is the anode (+). (a) False (b) True
28. 28.⚡ A device works on 6 V and takes 1.5 A. What is its power (in watts)? =
29. 29.True or false: current is measured in watts (W). (a) True (b) False
30. 30.🌈 A resistor has the colour bands yellow, white, red. What is its value (in ohms)?
31. 31.🧾 Which lamp gives the same light for the least power? (a) an oil lamp (b) an LED lamp (c) a candle (d) a filament bulb
32. 32.🔺 A current of 10 mA flows when 1.2 V is joined across a resistor. What is its resistance (in ohms)?
33. 33.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark an 860 Ω resistor? (a) grey-blue-brown (b) grey-blue-red (c) grey-blue-black (d) blue-grey-brown
34. 34.🔺 A current of 0.1 A flows when 0.4 V is joined across a resistor. What is its resistance (in ohms)?
35. 35.🌈 A resistor has the colour bands violet, grey, orange. What is its value (in ohms)?
36. 36.🔺 A current of 0.1 A flows when 0.2 V is joined across a resistor. What is its resistance (in ohms)?
37. 37.🧾 A family uses 40 units of electricity in a month and each unit costs ₹6. What is the bill (in ₹)?
38. 38.True or false: a buzzer makes a beeping sound. (a) False (b) True
39. 39.🧩 Which component makes things spin? (a) potentiometer (b) diode (c) transistor (d) motor
40. 40.🔺 A current of 2 A flows when 6 V is joined across a resistor. What is its resistance (in ohms)?

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