Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 617 · 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.🧮 Two resistors in parallel give a total that is … (a) always zero (b) their sum (c) less than either one (d) more than either one
2. 2.🌈 In the resistor colour code, which number does orange stand for?
3. 3.⚡ A 10 W device works on 5 V. What current does it take (in amperes)? =
4. 4.🔺 A current of 2.5 A flows when 30 V is joined across a resistor. What is its resistance (in ohms)?
5. 5.🧾 One “unit” on an electricity bill is … (a) 1 ampere (b) 1 volt (c) 1 watt (d) 1 kilowatt-hour (kWh)
6. 6.🔺 A current of 25 mA flows when 5 V is joined across a resistor. What is its resistance (in ohms)?
7. 7.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V + I (c) P = V × I (d) P = V ÷ I
8. 8.🌈 A gold fourth band on a resistor means the value may be off by … (a) 0 % (b) 50 % (c) 5 % (d) 25 %
9. 9.🔺 A current of 50 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
10. 10.🔺 A current of 50 mA flows through a 470 Ω resistor. What is the voltage across it (in volts)? =
11. 11.🧮 A 1.4 V battery is joined to 2 Ω and 5 Ω resistors in series. What current flows (in amperes)? =
12. 12.🧾 A family uses 170 units of electricity in a month and each unit costs ₹8. What is the bill (in ₹)?
13. 13.🧮 A 6 V battery is joined to 4 Ω and 2 Ω resistors in series. What current flows (in amperes)? =
14. 14.🌈 A resistor has the colour bands brown, black, red. What is its value in kilo-ohms (kΩ)? =
15. 15.🔺 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
16. 16.📏 In the water-pipe picture of a circuit, resistance is like … (a) the flow of water (b) a narrow pipe (c) a bigger tank (d) the water pressure
17. 17.📏 In the water-pipe picture of a circuit, voltage is like … (a) the water tank lid (b) the pipe colour (c) the water pressure (d) the tap handle
18. 18.🌈 A resistor has the colour bands blue, yellow, orange. What is its value in kilo-ohms (kΩ)? =
19. 19.🔺 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
20. 20.📏 Which unit measures resistance? (a) watt (W) (b) ohm (Ω) (c) ampere (A) (d) volt (V)
21. 21.🔺 An 8.8 V supply is joined across a 220 Ω resistor. What current flows (in milliamperes, mA)?
22. 22.⚡ A device works on 3 V and takes 1 A. What is its power (in watts)? =
23. 23.⚡ A home appliance on the 230 V mains takes 1.5 A. What is its power (in watts)?
24. 24.Which of these saves electricity? (a) leave fridge door open (b) iron one shirt at a time (c) use old filament bulbs (d) switch off empty rooms
25. 25.🌈 In the resistor colour code, which number does red stand for?
26. 26.💡 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
27. 27.🌈 A resistor has the colour bands grey, black, orange. What is its value (in ohms)?
28. 28.What does a resistor do? (a) makes things spin (b) senses how hot it is (c) stores a little charge (d) has coloured bands
29. 29.🔺 A 9.4 V supply is joined across a 470 Ω resistor. What current flows (in milliamperes, mA)?
30. 30.🧮 Three equal 150 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
31. 31.🧾 A family uses 20 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
32. 32.🔺 A current of 1.5 A flows when 22.5 V is joined across a resistor. What is its resistance (in ohms)?
33. 33.🌈 In the resistor colour code, which number does green stand for?
34. 34.💡 Why does an LED need a resistor in series? (a) to store charge (b) to change its colour (c) to make it brighter (d) to limit the current
35. 35.🔺 A current of 1 A flows when 8 V is joined across a resistor. What is its resistance (in ohms)?
36. 36.🌈 A resistor has the colour bands red, blue, brown. What is its value (in ohms)?
37. 37.⚡ A home appliance on the 230 V mains takes 8 A. What is its power (in watts)?
38. 38.⚡ A home appliance on the 230 V mains takes 10 A. What is its power (in watts)?
39. 39.🔺 A current of 2.5 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
40. 40.🌈 A resistor has the colour bands red, white, yellow. What is its value in kilo-ohms (kΩ)? =

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