Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 468 · 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.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark an 800 Ω resistor? (a) grey-black-black (b) grey-black-red (c) grey-black-brown (d) white-grey-brown
2. 2.🧮 A 20 Ω resistor is joined in series with two equal 100 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
3. 3.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 42000 Ω resistor? (a) yellow-red-red (b) yellow-red-orange (c) red-yellow-orange (d) yellow-red-yellow
4. 4.True or false: the voltmeter measures current. (a) True (b) False
5. 5.🔺 A current of 0.2 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
6. 6.⚡ Which formula gives electric power? (a) P = V ÷ I (b) P = I ÷ V (c) P = V × I (d) P = V + I
7. 7.🔺 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
8. 8.🧮 Resistors of 10 Ω, 68 Ω, 150 Ω and 68 Ω are joined in series. What is the total resistance (in ohms)?
9. 9.💡 An LED is joined to a 5 V battery with no resistor; its long leg goes to the + side and its short leg to the − side. What happens? (a) lights up (b) does not light (c) may burn out
10. 10.🔺 A current of 0.25 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
11. 11.📏 Which unit measures power? (a) ampere (A) (b) volt (V) (c) watt (W) (d) ohm (Ω)
12. 12.💡 Does it save or waste electricity to use daylight to read? (a) saves electricity (b) wastes electricity
13. 13.Which of these is measured in watts (W)? (a) power (b) resistance (c) current (d) voltage
14. 14.🧮 A 1.6 V battery is joined to 12 Ω and 4 Ω resistors in series. What current flows (in amperes)? =
15. 15.🔺 A current of 10 mA flows through a 250 Ω resistor. What is the voltage across it (in volts)? =
16. 16.🧮 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
17. 17.⚡ A home appliance on the 230 V mains takes 1 A. What is its power (in watts)?
18. 18.⚡ A device works on 5 V and takes 2 A. What is its power (in watts)? =
19. 19.🧾 A family uses 90 units of electricity in a month and each unit costs ₹6. What is the bill (in ₹)?
20. 20.📏 Voltmeter or ammeter: which one is joined across a part? (a) ammeter (b) voltmeter
21. 21.💡 An LED is joined to a 12 V battery with no resistor; its long leg goes to the + side and its short leg to the − side. What happens? (a) lights up (b) does not light (c) may burn out
22. 22.🧾 Which lamp gives the same light for the least power? (a) an LED lamp (b) a filament bulb (c) an oil lamp (d) a candle
23. 23.🔺 A 7.5 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =
24. 24.📏 How many watts (W) is 3.9 kW?
25. 25.True or false: to set the AC to 24 °C wastes electricity. (a) True (b) False
26. 26.💡 What does LED stand for? (a) large electric dial (b) low energy device (c) light-emitting diode (d) light energy dial
27. 27.🌈 In the resistor colour code, which number does blue stand for?
28. 28.🔺 A current of 3 A flows when 30 V is joined across a resistor. What is its resistance (in ohms)?
29. 29.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
30. 30.📏 How many ohms make 1 kilo-ohm (kΩ)? (a) 100 (b) 1000 (c) 10 (d) 1024
31. 31.🌈 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
32. 32.🔺 A current of 3 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
33. 33.True or false: to switch off empty rooms wastes electricity. (a) False (b) True
34. 34.True or false: to iron one shirt at a time saves electricity. (a) True (b) False
35. 35.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
36. 36.🌈 A resistor has the colour bands grey, grey, yellow. What is its value in kilo-ohms (kΩ)? =
37. 37.🔺 A current of 25 mA flows when 7.5 V is joined across a resistor. What is its resistance (in ohms)?
38. 38.🌈 A resistor has the colour bands yellow, grey, red. What is its value (in ohms)?
39. 39.🌈 A resistor has the colour bands grey, grey, orange. What is its value in kilo-ohms (kΩ)? =
40. 40.True or false: on an LED, the shorter leg is the anode (+). (a) False (b) True

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