Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 601 · 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 yellow, brown, red. What is its value in kilo-ohms (kΩ)? =
2. 2.🌈 A resistor has the colour bands brown, blue, brown. What is its value (in ohms)?
3. 3.📏 Which unit measures the push of a cell? (a) watt (W) (b) ohm (Ω) (c) volt (V) (d) ampere (A)
4. 4.🧩 Which component makes things spin? (a) motor (b) thermistor (c) resistor (d) diode
5. 5.🔺 A current of 0.5 A flows through a 15 Ω resistor. What is the voltage across it (in volts)? =
6. 6.🧩 Which component smooths a wobbly supply? (a) capacitor (b) thermistor (c) motor (d) potentiometer
7. 7.⚡ Power tells us … (a) energy used each second (b) the length of a wire (c) the size of a cell (d) the colour of light
8. 8.🔺 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
9. 9.💡 A red LED uses 2 V and should get 20 mA. It runs from a 5 V supply. What resistor (in ohms) is needed in series?
10. 10.🔺 A current of 2.5 A flows when 10 V is joined across a resistor. What is its resistance (in ohms)?
11. 11.🔺 A current of 1.5 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
12. 12.📏 Voltmeter or ammeter: which one measures current? (a) ammeter (b) voltmeter
13. 13.🌈 In the resistor colour code, which number does black stand for?
14. 14.What does a transistor do? (a) turns a fan or wheels (b) blows if current is high (c) senses how bright it is (d) boosts a small signal
15. 15.🌈 A resistor has the colour bands white, red, orange. What is its value in kilo-ohms (kΩ)? =
16. 16.🧾 A 50 W appliance runs for 6 hours. How many units (kWh) of electricity does it use? =
17. 17.⚡ A home appliance on the 230 V mains takes 5 A. What is its power (in watts)?
18. 18.🧮 A 50 Ω resistor is joined in series with two equal 200 Ω resistors that are in parallel with each other. What is the total resistance (in ohms)?
19. 19.🧮 A 7 V battery is joined to 6 Ω and 8 Ω resistors in series. What current flows (in amperes)? =
20. 20.🧮 Resistors of 50 Ω, 100 Ω and 22 Ω are joined in series. What is the total resistance (in ohms)?
21. 21.📏 Which unit measures voltage? (a) ohm (Ω) (b) ampere (A) (c) volt (V) (d) watt (W)
22. 22.⚡ A 0.375 W device works on 1.5 V. What current does it take (in amperes)? =
23. 23.⚡ A home appliance on the 230 V mains takes 1 A. What is its power (in watts)?
24. 24.🔺 A current of 0.1 A flows when 1.5 V is joined across a resistor. What is its resistance (in ohms)?
25. 25.🧮 Adding another resistor in series makes the total resistance … (a) stay the same (b) bigger (c) smaller (d) zero
26. 26.🧾 A 75 W filament bulb is swapped for a 12 W LED lamp that gives about the same light. Both would run for 10 hours. How many watt-hours (Wh) are saved?
27. 27.🧮 Four equal 20 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
28. 28.🔺 A 7.5 V supply is joined across a 3 Ω resistor. What current flows (in amperes)? =
29. 29.🧩 Which component turns a fan or wheels? (a) LDR (b) capacitor (c) fuse (d) motor
30. 30.🔺 In the V-I-R triangle, how do we find V? (a) V = I × R (b) V = I + R (c) V = R ÷ I (d) V = I ÷ R
31. 31.🌈 A resistor has the colour bands yellow, yellow, black. What is its value (in ohms)?
32. 32.🔺 A current of 25 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
33. 33.True or false: an LDR makes a beeping sound. (a) False (b) True
34. 34.⚡ A home appliance on the 230 V mains takes 1.5 A. What is its power (in watts)?
35. 35.What does an LDR do? (a) blows if current is high (b) makes a beeping sound (c) glows using little power (d) senses how bright it is
36. 36.🔺 A current of 40 mA flows through a 330 Ω resistor. What is the voltage across it (in volts)? =
37. 37.⚡ A device works on 1.5 V and takes 0.2 A. What is its power (in watts)? =
38. 38.What does a potentiometer do? (a) lets current go one way (b) is a resistance knob (c) has coloured bands (d) beeps for an alarm
39. 39.🧾 A family uses 160 units of electricity in a month and each unit costs ₹6. What is the bill (in ₹)?
40. 40.📏 How many amperes (A) is 690 mA? =

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