Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 969 · 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 current of 10 mA flows through a 500 Ω resistor. What is the voltage across it (in volts)? =
2. 2.🔺 In the V-I-R triangle, how do we find R? (a) R = V × I (b) R = V ÷ I (c) R = V + I (d) R = I ÷ V
3. 3.📏 How many kilo-ohms (kΩ) is 1000 Ω? =
4. 4.🔍 Which is the odd one out? (a) set the AC to 24 °C (b) unplug idle chargers (c) use LED lamps (d) run fans in empty rooms
5. 5.📏 Which unit measures resistance? (a) ohm (Ω) (b) ampere (A) (c) watt (W) (d) volt (V)
6. 6.🧾 Which lamp gives the same light for the least power? (a) an oil lamp (b) a candle (c) an LED lamp (d) a filament bulb
7. 7.🧩 Which component makes things spin? (a) potentiometer (b) motor (c) resistor (d) capacitor
8. 8.🔺 A 5 V supply is joined across a 100 Ω resistor. What current flows (in milliamperes, mA)?
9. 9.🔺 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
10. 10.🧩 Which component makes a beeping sound? (a) thermistor (b) potentiometer (c) LDR (d) buzzer
11. 11.⚡ A device works on 24 V and takes 1.5 A. What is its power (in watts)? =
12. 12.🌈 A resistor has the colour bands grey, blue, yellow. What is its value in kilo-ohms (kΩ)? =
13. 13.🧩 Which part changes electrical energy into movement? (a) a resistor (b) an LED (c) a fuse (d) a motor
14. 14.⚡ A home appliance on the 230 V mains takes 0.5 A. What is its power (in watts)?
15. 15.True or false: a resistor smooths a wobbly supply. (a) True (b) False
16. 16.⚡ A home appliance on the 230 V mains takes 2 A. What is its power (in watts)?
17. 17.True or false: on an LED, the longer leg is the cathode (−). (a) False (b) True
18. 18.📏 Which unit measures voltage? (a) watt (W) (b) ampere (A) (c) ohm (Ω) (d) volt (V)
19. 19.🧮 Two equal 40 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
20. 20.💡 A red LED (it uses 2 V) is joined with a 200 Ω resistor to a 4 V supply. What current flows (in mA)?
21. 21.🔺 A current of 10 mA flows through a 120 Ω resistor. What is the voltage across it (in volts)? =
22. 22.🧮 Two equal 20 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
23. 23.🧾 A family uses 20 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
24. 24.⚡ A 12 W device works on 24 V. What current does it take (in amperes)? =
25. 25.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark an 850 Ω resistor? (a) green-grey-brown (b) grey-green-red (c) grey-green-brown (d) grey-green-black
26. 26.🧮 Two equal 220 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
27. 27.Which of these wastes electricity? (a) use LED lamps (b) run fans in empty rooms (c) unplug idle chargers (d) close the fridge quickly
28. 28.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 5400 Ω resistor? (a) green-yellow-red (b) yellow-green-red (c) green-yellow-orange (d) green-yellow-brown
29. 29.🌈 In the resistor colour code, which number does violet stand for?
30. 30.🔍 Which is the odd one out? (a) leave fridge door open (b) use LED lamps (c) leave the TV on standby (d) use old filament bulbs
31. 31.💡 An LED is joined to a 3 V battery through a 220 Ω resistor; the leg next to the flat edge of its rim goes to the − side. What happens? (a) does not light (b) may burn out (c) lights up
32. 32.What does a capacitor do? (a) beeps for an alarm (b) smooths a wobbly supply (c) has coloured bands (d) boosts a small signal
33. 33.True or false: the push of a cell is measured in ohms (Ω). (a) False (b) True
34. 34.🧮 Adding another resistor in series makes the total resistance … (a) bigger (b) smaller (c) stay the same (d) zero
35. 35.🔺 A current of 3 A flows through a 3 Ω resistor. What is the voltage across it (in volts)? =
36. 36.🧩 A capacitor in a circuit can … (a) make light (b) measure heat (c) store charge briefly (d) spin a wheel
37. 37.⚡ Power tells us … (a) the length of a wire (b) the colour of light (c) the size of a cell (d) energy used each second
38. 38.📏 Which unit measures the flow of charge? (a) ohm (Ω) (b) ampere (A) (c) volt (V) (d) watt (W)
39. 39.📏 How many milliamperes (mA) make 1 ampere? (a) 100 (b) 1000 (c) 10 (d) 60
40. 40.🌈 A resistor has the colour bands red, brown, black. What is its value (in ohms)?

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