Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 752 · 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 family uses 160 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
2. 2.True or false: on an LED, the leg by the flat edge is the anode (+). (a) False (b) True
3. 3.🔺 A current of 20 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
4. 4.🔺 A current of 2 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
5. 5.🧩 Which component limits the current? (a) LDR (b) LED (c) thermistor (d) resistor
6. 6.🔺 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
7. 7.🧩 Which part changes electrical energy into sound? (a) a capacitor (b) a resistor (c) a diode (d) a buzzer
8. 8.🌈 A resistor has the colour bands grey, black, red. What is its value (in ohms)?
9. 9.🌈 A resistor has the colour bands violet, black, orange. What is its value in kilo-ohms (kΩ)? =
10. 10.True or false: voltage is measured in watts (W). (a) True (b) False
11. 11.True or false: on an LED, the longer leg is the anode (+). (a) False (b) True
12. 12.🌈 A gold fourth band on a resistor means the value may be off by … (a) 25 % (b) 0 % (c) 5 % (d) 50 %
13. 13.Which of these is measured in volts (V)? (a) voltage (b) resistance (c) current (d) how much a part resists
14. 14.📏 How many milliamperes (mA) is 0.81 A?
15. 15.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 61 Ω resistor? (a) brown-blue-black (b) violet-brown-black (c) blue-brown-brown (d) blue-brown-black
16. 16.🧮 Resistors of 470 Ω, 68 Ω, 33 Ω and 50 Ω are joined in series. What is the total resistance (in ohms)?
17. 17.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
18. 18.🧩 Which component stores a little charge? (a) potentiometer (b) capacitor (c) fuse (d) transistor
19. 19.💡 What does LED stand for? (a) large electric dial (b) low energy device (c) light-emitting diode (d) light energy dial
20. 20.⚡ A device works on 3 V and takes 1 A. What is its power (in watts)? =
21. 21.🔺 In the V-I-R triangle, how do we find I? (a) I = V ÷ R (b) I = V × R (c) I = R ÷ V (d) I = V + R
22. 22.🔍 Which is the odd one out? (a) use old filament bulbs (b) switch off empty rooms (c) leave the TV on standby (d) leave fridge door open
23. 23.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 55000 Ω resistor? (a) green-green-red (b) green-green-yellow (c) green-green-orange (d) green-blue-orange
24. 24.True or false: to use old filament bulbs wastes electricity. (a) False (b) True
25. 25.🔺 A current of 2 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
26. 26.📏 In the water-pipe picture of a circuit, current is like … (a) the flow of water (b) a narrow pipe (c) the pipe colour (d) the water pressure
27. 27.🧾 A family uses 70 units of electricity in a month and each unit costs ₹5. What is the bill (in ₹)?
28. 28.🌈 A resistor has the colour bands blue, brown, orange. What is its value in kilo-ohms (kΩ)? =
29. 29.⚡ Power tells us … (a) the length of a wire (b) the colour of light (c) energy used each second (d) the size of a cell
30. 30.🌈 A resistor has the colour bands blue, red, black. What is its value (in ohms)?
31. 31.💡 An LED is joined to a 5 V battery with no resistor; the leg next to the flat edge of its rim goes to the − side. What happens? (a) lights up (b) does not light (c) may burn out
32. 32.💡 Does it save or waste electricity to set the AC to 24 °C? (a) wastes electricity (b) saves electricity
33. 33.🧩 Which part changes electrical energy into movement? (a) an LED (b) a motor (c) a resistor (d) a fuse
34. 34.🔍 Which is the odd one out? (a) close the fridge quickly (b) run fans in empty rooms (c) unplug idle chargers (d) use daylight to read
35. 35.🔺 A current of 20 mA flows through a 120 Ω resistor. What is the voltage across it (in volts)? =
36. 36.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V × I (c) P = V + I (d) P = V ÷ I
37. 37.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 6000 Ω resistor? (a) blue-black-orange (b) blue-black-brown (c) blue-black-red (d) violet-blue-red
38. 38.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
39. 39.True or false: the voltmeter is joined in series. (a) True (b) False
40. 40.🔺 A current of 2.5 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =

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