Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 859 · 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 36 W device works on 12 V. What current does it take (in amperes)? =
2. 2.True or false: on an LED, the shorter leg is the anode (+). (a) True (b) False
3. 3.🔺 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
4. 4.🔺 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
5. 5.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 74 Ω resistor? (a) violet-yellow-brown (b) grey-yellow-black (c) violet-yellow-black (d) yellow-violet-black
6. 6.🧮 Resistors of 10 Ω, 47 Ω and 20 Ω are joined in series. What is the total resistance (in ohms)?
7. 7.🧮 A 9 V battery is joined to 3 Ω and 6 Ω resistors in series. What current flows (in amperes)? =
8. 8.📏 How many kilo-ohms (kΩ) is 5900 Ω? =
9. 9.🧾 A family uses 50 units of electricity in a month and each unit costs ₹8. What is the bill (in ₹)?
10. 10.🔺 A current of 40 mA flows when 18.8 V is joined across a resistor. What is its resistance (in ohms)?
11. 11.🌈 A resistor has the colour bands red, black, red. What is its value (in ohms)?
12. 12.💡 What does LED stand for? (a) large electric dial (b) low energy device (c) light energy dial (d) light-emitting diode
13. 13.🔺 In the V-I-R triangle, how do we find R? (a) R = V + I (b) R = I ÷ V (c) R = V ÷ I (d) R = V × I
14. 14.💡 Does it save or waste electricity to switch off empty rooms? (a) wastes electricity (b) saves electricity
15. 15.Which of these saves electricity? (a) use daylight to read (b) iron one shirt at a time (c) leave the TV on standby (d) run fans in empty rooms
16. 16.🔺 A current of 0.2 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
17. 17.🧮 A 33 Ω resistor is joined in series with two equal 10 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
18. 18.🧮 Two resistors in parallel give a total that is … (a) more than either one (b) always zero (c) less than either one (d) their sum
19. 19.🔺 A 1 V supply is joined across a 100 Ω resistor. What current flows (in milliamperes, mA)?
20. 20.🔺 A current of 3 A flows through a 2 Ω resistor. What is the voltage across it (in volts)? =
21. 21.🧮 Adding another resistor in series makes the total resistance … (a) stay the same (b) smaller (c) bigger (d) zero
22. 22.🌈 A resistor has the colour bands white, green, orange. What is its value in kilo-ohms (kΩ)? =
23. 23.🔺 A current of 0.2 A flows when 0.6 V is joined across a resistor. What is its resistance (in ohms)?
24. 24.⚡ A device works on 3 V and takes 1.5 A. What is its power (in watts)? =
25. 25.📏 How many amperes (A) is 1520 mA? =
26. 26.🧾 One “unit” on an electricity bill is … (a) 1 kilowatt-hour (kWh) (b) 1 ampere (c) 1 watt (d) 1 volt
27. 27.🔺 A current of 50 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
28. 28.🔺 A current of 40 mA flows through a 250 Ω resistor. What is the voltage across it (in volts)? =
29. 29.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) stays the same (b) gets bigger (c) gets smaller (d) becomes zero
30. 30.🌈 A resistor has the colour bands white, grey, black. What is its value (in ohms)?
31. 31.📏 In the water-pipe picture of a circuit, voltage is like … (a) the water tank lid (b) the water pressure (c) the tap handle (d) the pipe colour
32. 32.📏 In the water-pipe picture of a circuit, current is like … (a) the flow of water (b) the water pressure (c) the pipe colour (d) a narrow pipe
33. 33.🌈 A resistor has the colour bands yellow, green, red. What is its value (in ohms)?
34. 34.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
35. 35.🧩 Which part changes electrical energy into movement? (a) an LED (b) a fuse (c) a resistor (d) a motor
36. 36.⚡ A home appliance on the 230 V mains takes 1.5 A. What is its power (in watts)?
37. 37.🧮 Resistors of 47 Ω and 220 Ω are joined in series. What is the total resistance (in ohms)?
38. 38.🔺 A current of 2 A flows when 30 V is joined across a resistor. What is its resistance (in ohms)?
39. 39.⚡ A home appliance on the 230 V mains takes 5 A. What is its power (in watts)?
40. 40.True or false: to iron one shirt at a time saves electricity. (a) True (b) False

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