Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 635 · 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.True or false: on an LED, the leg by the flat edge is the cathode (−). (a) True (b) False
2. 2.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
3. 3.🔺 A 4 V supply is joined across a 2 Ω resistor. What current flows (in amperes)? =
4. 4.🔺 A 4 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
5. 5.🔺 A current of 20 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
6. 6.🔺 A current of 2 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
7. 7.🧮 A 68 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)?
8. 8.⚡ A home appliance on the 230 V mains takes 0.5 A. What is its power (in watts)?
9. 9.⚡ A device works on 3 V and takes 1 A. What is its power (in watts)? =
10. 10.⚡ A device works on 12 V and takes 3 A. What is its power (in watts)? =
11. 11.True or false: a potentiometer stores a little charge. (a) False (b) True
12. 12.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 98 Ω resistor? (a) brown-grey-black (b) white-grey-black (c) white-grey-brown (d) grey-white-black
13. 13.⚡ Power tells us … (a) the length of a wire (b) energy used each second (c) the colour of light (d) the size of a cell
14. 14.🔺 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
15. 15.📏 In the water-pipe picture of a circuit, voltage is like … (a) the water tank lid (b) the water pressure (c) the pipe colour (d) the tap handle
16. 16.True or false: resistance is measured in amperes (A). (a) False (b) True
17. 17.🧾 A family uses 150 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
18. 18.True or false: on an LED, the round-side leg is the cathode (−). (a) True (b) False
19. 19.True or false: on an LED, the shorter leg is the cathode (−). (a) False (b) True
20. 20.🧮 Two equal 40 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
21. 21.Which of these is measured in watts (W)? (a) voltage (b) current (c) resistance (d) energy used each second
22. 22.🧮 Resistors of 20 Ω and 220 Ω are joined in series. What is the total resistance (in ohms)?
23. 23.🌈 A resistor has the colour bands orange, blue, orange. What is its value in kilo-ohms (kΩ)? =
24. 24.🧩 Which component beeps for an alarm? (a) capacitor (b) LED (c) thermistor (d) buzzer
25. 25.🌈 Which band is read first on a resistor? (a) any band (b) the widest gap (c) the one nearest an end (d) the gold band
26. 26.🔺 A current of 0.25 A flows when 0.75 V is joined across a resistor. What is its resistance (in ohms)?
27. 27.🔺 A current of 10 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
28. 28.🌈 A resistor has the colour bands red, yellow, yellow. What is its value in kilo-ohms (kΩ)? =
29. 29.💡 On an LED, is the longer leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
30. 30.🔺 A current of 2 A flows through an 8 Ω resistor. What is the voltage across it (in volts)? =
31. 31.🧮 Four equal 20 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
32. 32.🔺 A current of 40 mA flows when 4 V is joined across a resistor. What is its resistance (in ohms)?
33. 33.🔺 A current of 2.5 A flows when 20 V is joined across a resistor. What is its resistance (in ohms)?
34. 34.🧮 A 33 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)?
35. 35.Which of these is measured in volts (V)? (a) current (b) the push of a cell (c) the flow of charge (d) power
36. 36.🔺 A 30 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
37. 37.💡 What does LED stand for? (a) low energy device (b) light-emitting diode (c) light energy dial (d) large electric dial
38. 38.📏 How many watts (W) is 2.7 kW?
39. 39.🌈 A resistor has the colour bands red, white, orange. What is its value (in ohms)?
40. 40.🌈 A resistor has the colour bands grey, blue, black. What is its value (in ohms)?

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