Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 662 · 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.🧮 Resistors of 68 Ω, 20 Ω, 68 Ω and 470 Ω are joined in series. What is the total resistance (in ohms)?
2. 2.🔺 A current of 40 mA flows through a 220 Ω resistor. What is the voltage across it (in volts)? =
3. 3.🔺 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
4. 4.🧮 Adding another resistor in series makes the total resistance … (a) bigger (b) stay the same (c) smaller (d) zero
5. 5.🔺 A 20 V supply is joined across a 10 Ω resistor. What current flows (in amperes)? =
6. 6.🧮 Two resistors in parallel give a total that is … (a) more than either one (b) less than either one (c) their sum (d) always zero
7. 7.🧩 Which part changes electrical energy into movement? (a) a resistor (b) a motor (c) an LED (d) a fuse
8. 8.🔺 A 4 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
9. 9.🧾 A family uses 30 units of electricity in a month and each unit costs ₹9. What is the bill (in ₹)?
10. 10.💡 Does it save or waste electricity to switch off empty rooms? (a) wastes electricity (b) saves electricity
11. 11.🌈 In the resistor colour code, which number does black stand for?
12. 12.🔺 A 15 V supply is joined across a 300 Ω resistor. What current flows (in milliamperes, mA)?
13. 13.🧮 A 68 Ω resistor is joined in series with two equal 20 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
14. 14.📏 How many watts (W) is 1.3 kW?
15. 15.🧮 A 5.5 V battery is joined to 3 Ω and 8 Ω resistors in series. What current flows (in amperes)? =
16. 16.⚡ A 2.4 W device works on 24 V. What current does it take (in amperes)? =
17. 17.🧩 Which component is a resistance knob? (a) potentiometer (b) diode (c) resistor (d) LDR
18. 18.📏 Which unit measures current? (a) ampere (A) (b) ohm (Ω) (c) watt (W) (d) volt (V)
19. 19.True or false: on an LED, the leg by the flat edge is the cathode (−). (a) False (b) True
20. 20.🌈 A gold fourth band on a resistor means the value may be off by … (a) 25 % (b) 5 % (c) 50 % (d) 0 %
21. 21.⚡ A home appliance on the 230 V mains takes 5 A. What is its power (in watts)?
22. 22.⚡ A 15 W device works on 5 V. What current does it take (in amperes)? =
23. 23.🔺 A current of 25 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
24. 24.💡 On an LED, is the round-side leg the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
25. 25.🌈 A resistor has the colour bands red, green, orange. What is its value in kilo-ohms (kΩ)? =
26. 26.🔺 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
27. 27.🔺 A 7.5 V supply is joined across a 150 Ω resistor. What current flows (in milliamperes, mA)?
28. 28.🧾 A 50 W appliance runs for 5 hours. How many units (kWh) of electricity does it use? =
29. 29.⚡ A device works on 6 V and takes 0.1 A. What is its power (in watts)? =
30. 30.💡 Does it save or waste electricity to use daylight to read? (a) saves electricity (b) wastes electricity
31. 31.🔍 Which is the odd one out? (a) leave the TV on standby (b) use LED lamps (c) switch off empty rooms (d) use daylight to read
32. 32.🔍 Which is the odd one out? (a) iron one shirt at a time (b) switch off empty rooms (c) leave fridge door open (d) run fans in empty rooms
33. 33.🔺 A 4.7 V supply is joined across a 470 Ω resistor. What current flows (in milliamperes, mA)?
34. 34.🌈 A resistor has the colour bands green, orange, brown. What is its value (in ohms)?
35. 35.🔺 A current of 10 mA flows when 5 V is joined across a resistor. What is its resistance (in ohms)?
36. 36.🔺 A current of 10 mA flows through a 250 Ω resistor. What is the voltage across it (in volts)? =
37. 37.Which of these is measured in amperes (A)? (a) resistance (b) the push of a cell (c) energy used each second (d) current
38. 38.🔺 A current of 1.5 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
39. 39.🔺 A current of 0.25 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
40. 40.⚡ A device works on 24 V and takes 2 A. What is its power (in watts)? =

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