Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 191 · 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 is the odd one out? (a) use old filament bulbs (b) use LED lamps (c) run fans in empty rooms (d) iron one shirt at a time
2. 2.📏 How many kilo-ohms (kΩ) is 5300 Ω? =
3. 3.🧮 Adding another resistor in series makes the total resistance … (a) stay the same (b) zero (c) bigger (d) smaller
4. 4.🔺 A current of 20 mA flows through a 120 Ω resistor. What is the voltage across it (in volts)? =
5. 5.🔺 A current of 25 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
6. 6.True or false: the voltmeter measures voltage. (a) True (b) False
7. 7.🧮 Five equal 100 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
8. 8.⚡ A device works on 24 V and takes 3 A. What is its power (in watts)? =
9. 9.🧮 A 0.7 V battery is joined to 3 Ω and 4 Ω resistors in series. What current flows (in amperes)? =
10. 10.🔺 A current of 40 mA flows through a 470 Ω resistor. What is the voltage across it (in volts)? =
11. 11.💡 A red LED (it uses 2 V) is joined with a 150 Ω resistor to a 5 V supply. What current flows (in mA)?
12. 12.🔺 A current of 2 A flows when 16 V is joined across a resistor. What is its resistance (in ohms)?
13. 13.What does a potentiometer do? (a) is a resistance knob (b) glows using little power (c) blows if current is high (d) turns a fan or wheels
14. 14.🧾 A family uses 60 units of electricity in a month and each unit costs ₹6. What is the bill (in ₹)?
15. 15.🔺 A current of 0.1 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
16. 16.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 43000 Ω resistor? (a) orange-yellow-orange (b) yellow-orange-orange (c) yellow-orange-yellow (d) yellow-orange-red
17. 17.⚡ A 10 W device works on 5 V. What current does it take (in amperes)? =
18. 18.⚡ Power tells us … (a) energy used each second (b) the colour of light (c) the length of a wire (d) the size of a cell
19. 19.🔺 A current of 3 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
20. 20.📏 How many kilowatts (kW) is 2000 W? =
21. 21.💡 What happens if an LED is put in backwards? (a) it lights brighter (b) it changes colour (c) it makes a sound (d) it does not light
22. 22.🔺 A current of 0.2 A flows when 1 V is joined across a resistor. What is its resistance (in ohms)?
23. 23.🌈 A resistor has the colour bands white, red, black. What is its value (in ohms)?
24. 24.🧾 A 60 W filament bulb is swapped for a 9 W LED lamp that gives about the same light. Both would run for 3 hours. How many watt-hours (Wh) are saved?
25. 25.🌈 A resistor has the colour bands blue, blue, orange. What is its value (in ohms)?
26. 26.🧮 Resistors of 50 Ω and 220 Ω are joined in series. What is the total resistance (in ohms)?
27. 27.🧮 A 100 Ω resistor is joined in series with two equal 40 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
28. 28.🔺 A 16.5 V supply is joined across a 330 Ω resistor. What current flows (in milliamperes, mA)?
29. 29.True or false: the voltmeter measures current. (a) True (b) False
30. 30.🌈 In the resistor colour code, which number does red stand for?
31. 31.🔺 A current of 0.2 A flows when 0.8 V is joined across a resistor. What is its resistance (in ohms)?
32. 32.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 33000 Ω resistor? (a) orange-yellow-orange (b) orange-orange-yellow (c) orange-orange-red (d) orange-orange-orange
33. 33.⚡ A home appliance on the 230 V mains takes 10 A. What is its power (in watts)?
34. 34.Which of these saves electricity? (a) unplug idle chargers (b) run fans in empty rooms (c) use old filament bulbs (d) iron one shirt at a time
35. 35.🔺 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
36. 36.Which of these wastes electricity? (a) switch off empty rooms (b) close the fridge quickly (c) use LED lamps (d) iron one shirt at a time
37. 37.📏 How many ohms (Ω) is 5.2 kΩ?
38. 38.🔺 A current of 0.2 A flows through a 10 Ω resistor. What is the voltage across it (in volts)? =
39. 39.True or false: current is measured in watts (W). (a) True (b) False
40. 40.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) becomes zero (b) stays the same (c) gets bigger (d) gets smaller

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