Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 228 · 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 12 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
2. 2.💡 Does it save or waste electricity to leave fridge door open? (a) saves electricity (b) wastes electricity
3. 3.📏 How many kilo-ohms (kΩ) is 1700 Ω? =
4. 4.🌈 A resistor has the colour bands blue, grey, orange. What is its value in kilo-ohms (kΩ)? =
5. 5.🧩 A capacitor in a circuit can … (a) store charge briefly (b) make light (c) spin a wheel (d) measure heat
6. 6.Which of these is measured in volts (V)? (a) power (b) voltage (c) the flow of charge (d) resistance
7. 7.💡 Does it save or waste electricity to iron one shirt at a time? (a) saves electricity (b) wastes electricity
8. 8.🧩 Which component boosts a small signal? (a) buzzer (b) resistor (c) LED (d) transistor
9. 9.🔺 A current of 50 mA flows through a 120 Ω resistor. What is the voltage across it (in volts)? =
10. 10.🌈 Which band is read first on a resistor? (a) any band (b) the gold band (c) the one nearest an end (d) the widest gap
11. 11.🔺 A current of 3 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
12. 12.🔺 A current of 0.2 A flows when 1.2 V is joined across a resistor. What is its resistance (in ohms)?
13. 13.🔺 A current of 0.2 A flows when 1.6 V is joined across a resistor. What is its resistance (in ohms)?
14. 14.🔺 In the V-I-R triangle, how do we find I? (a) I = V × R (b) I = R ÷ V (c) I = V ÷ R (d) I = V + R
15. 15.True or false: the voltmeter measures voltage. (a) False (b) True
16. 16.Which of these is measured in ohms (Ω)? (a) resistance (b) voltage (c) power (d) current
17. 17.🌈 A gold fourth band on a resistor means the value may be off by … (a) 50 % (b) 0 % (c) 5 % (d) 25 %
18. 18.True or false: a potentiometer limits the current. (a) False (b) True
19. 19.🌈 A resistor has the colour bands grey, red, red. What is its value (in ohms)?
20. 20.🧮 A 1.6 V battery is joined to 10 Ω and 6 Ω resistors in series. What current flows (in amperes)? =
21. 21.🧾 A family uses 20 units of electricity in a month and each unit costs ₹6. What is the bill (in ₹)?
22. 22.💡 Does it save or waste electricity to switch off empty rooms? (a) wastes electricity (b) saves electricity
23. 23.📏 How many ohms make 1 kilo-ohm (kΩ)? (a) 10 (b) 1000 (c) 1024 (d) 100
24. 24.🌈 In the resistor colour code, which number does brown stand for?
25. 25.🔺 A current of 3 A flows when 24 V is joined across a resistor. What is its resistance (in ohms)?
26. 26.🔺 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
27. 27.True or false: a capacitor smooths a wobbly supply. (a) False (b) True
28. 28.What does a buzzer do? (a) blows if current is high (b) beeps for an alarm (c) turns a fan or wheels (d) is a resistance knob
29. 29.💡 What happens if an LED is put in backwards? (a) it makes a sound (b) it does not light (c) it changes colour (d) it lights brighter
30. 30.🔺 A current of 0.1 A flows when 0.6 V is joined across a resistor. What is its resistance (in ohms)?
31. 31.🔺 A 1.25 V supply is joined across a 5 Ω resistor. What current flows (in amperes)? =
32. 32.🔺 A current of 2.5 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
33. 33.🔺 A current of 10 mA flows through a 500 Ω resistor. What is the voltage across it (in volts)? =
34. 34.🌈 A resistor has the colour bands yellow, black, black. What is its value (in ohms)?
35. 35.🔺 A current of 2 A flows when 40 V is joined across a resistor. What is its resistance (in ohms)?
36. 36.🧩 Which component lets current go one way? (a) buzzer (b) motor (c) thermistor (d) diode
37. 37.🔺 A current of 0.1 A flows through a 5 Ω resistor. What is the voltage across it (in volts)? =
38. 38.🧾 Which lamp gives the same light for the least power? (a) a filament bulb (b) an oil lamp (c) an LED lamp (d) a candle
39. 39.💡 A red LED (it uses 2 V) is joined with a 200 Ω resistor to a 6 V supply. What current flows (in mA)?
40. 40.🌈 A resistor has the colour bands brown, green, orange. What is its value in kilo-ohms (kΩ)? =

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