Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 149 · 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.🌈 A resistor has the colour bands violet, blue, orange. What is its value (in ohms)?
2. 2.True or false: voltage is measured in watts (W). (a) False (b) True
3. 3.True or false: on an LED, the leg by the flat edge is the cathode (−). (a) True (b) False
4. 4.🧮 Two resistors in parallel give a total that is … (a) their sum (b) less than either one (c) always zero (d) more than either one
5. 5.📏 How many kilo-ohms (kΩ) is 9000 Ω? =
6. 6.🔺 A current of 0.25 A flows through a 6 Ω resistor. What is the voltage across it (in volts)? =
7. 7.⚡ A home appliance on the 230 V mains takes 10 A. What is its power (in watts)?
8. 8.🌈 A resistor has the colour bands grey, yellow, yellow. What is its value in kilo-ohms (kΩ)? =
9. 9.🧮 An 18 V battery is joined to 12 Ω and 6 Ω resistors in series. What current flows (in amperes)? =
10. 10.🧩 Which part changes electrical energy into sound? (a) a capacitor (b) a resistor (c) a diode (d) a buzzer
11. 11.🔺 A current of 50 mA flows through a 120 Ω resistor. What is the voltage across it (in volts)? =
12. 12.⚡ Which formula gives electric power? (a) P = I ÷ V (b) P = V × I (c) P = V ÷ I (d) P = V + I
13. 13.📏 Voltmeter or ammeter: which one measures voltage? (a) voltmeter (b) ammeter
14. 14.🧾 A family uses 30 units of electricity in a month and each unit costs ₹6. What is the bill (in ₹)?
15. 15.📏 How many kilo-ohms (kΩ) is 6800 Ω? =
16. 16.Which of these wastes electricity? (a) iron one shirt at a time (b) unplug idle chargers (c) use LED lamps (d) use daylight to read
17. 17.🔺 A current of 25 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
18. 18.🔺 A current of 25 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
19. 19.📏 In the water-pipe picture of a circuit, voltage is like … (a) the water pressure (b) the water tank lid (c) the tap handle (d) the pipe colour
20. 20.🔺 A current of 10 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
21. 21.💡 Why does an LED need a resistor in series? (a) to change its colour (b) to make it brighter (c) to store charge (d) to limit the current
22. 22.⚡ Power tells us … (a) energy used each second (b) the size of a cell (c) the colour of light (d) the length of a wire
23. 23.📏 Voltmeter or ammeter: which one measures current? (a) ammeter (b) voltmeter
24. 24.🔺 In the V-I-R triangle, how do we find I? (a) I = V + R (b) I = V × R (c) I = V ÷ R (d) I = R ÷ V
25. 25.🔺 A current of 25 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
26. 26.🧩 Which component makes a beeping sound? (a) LED (b) transistor (c) LDR (d) buzzer
27. 27.True or false: to run fans in empty rooms saves electricity. (a) True (b) False
28. 28.🔺 In the V-I-R triangle, how do we find R? (a) R = V + I (b) R = I ÷ V (c) R = V × I (d) R = V ÷ I
29. 29.🔺 A 2 V supply is joined across a 20 Ω resistor. What current flows (in amperes)? =
30. 30.🔺 A current of 10 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
31. 31.True or false: current is measured in ohms (Ω). (a) False (b) True
32. 32.What does a buzzer do? (a) makes things spin (b) beeps for an alarm (c) smooths a wobbly supply (d) stores a little charge
33. 33.📏 Voltmeter or ammeter: which one is joined in series? (a) voltmeter (b) ammeter
34. 34.🔺 A current of 0.5 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
35. 35.🔺 A current of 0.25 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
36. 36.🔺 A current of 20 mA flows through a 300 Ω resistor. What is the voltage across it (in volts)? =
37. 37.🌈 A resistor has the colour bands brown, blue, yellow. What is its value in kilo-ohms (kΩ)? =
38. 38.📏 Which unit measures the flow of charge? (a) ohm (Ω) (b) ampere (A) (c) watt (W) (d) volt (V)
39. 39.🔺 A current of 0.5 A flows when 2 V is joined across a resistor. What is its resistance (in ohms)?
40. 40.🔺 A current of 50 mA flows through a 500 Ω resistor. What is the voltage across it (in volts)? =

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