Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 252 · 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.🧮 Two equal 100 Ω resistors are joined in parallel. What is the total resistance (in ohms)?
2. 2.🧩 Which part changes electrical energy into movement? (a) a motor (b) a fuse (c) a resistor (d) an LED
3. 3.True or false: the voltmeter measures voltage. (a) True (b) False
4. 4.📏 How many kilowatts (kW) is 4250 W? =
5. 5.🔍 Which is the odd one out? (a) use LED lamps (b) use daylight to read (c) set the AC to 24 °C (d) iron one shirt at a time
6. 6.True or false: on an LED, the leg by the flat edge is the cathode (−). (a) True (b) False
7. 7.📏 How many milliamperes (mA) is 2.1 A?
8. 8.True or false: on an LED, the leg by the flat edge is the anode (+). (a) True (b) False
9. 9.What does a potentiometer do? (a) makes a beeping sound (b) limits the current (c) senses how hot it is (d) is a resistance knob
10. 10.🌈 A resistor has the colour bands green, blue, brown. What is its value (in ohms)?
11. 11.🌈 A resistor has the colour bands blue, brown, yellow. What is its value in kilo-ohms (kΩ)? =
12. 12.🌈 A resistor has the colour bands red, green, yellow. What is its value in kilo-ohms (kΩ)? =
13. 13.🔺 A current of 2 A flows when 4 V is joined across a resistor. What is its resistance (in ohms)?
14. 14.🧾 A family uses 30 units of electricity in a month and each unit costs ₹8. What is the bill (in ₹)?
15. 15.💡 Does it save or waste electricity to leave the TV on standby? (a) wastes electricity (b) saves electricity
16. 16.💡 Does it save or waste electricity to close the fridge quickly? (a) saves electricity (b) wastes electricity
17. 17.🔺 A current of 25 mA flows when 8.25 V is joined across a resistor. What is its resistance (in ohms)?
18. 18.🔍 Which is the odd one out? (a) leave fridge door open (b) use old filament bulbs (c) unplug idle chargers (d) iron one shirt at a time
19. 19.Which of these wastes electricity? (a) close the fridge quickly (b) use LED lamps (c) unplug idle chargers (d) run fans in empty rooms
20. 20.🧾 A family uses 180 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
21. 21.🧮 Two resistors in parallel give a total that is … (a) always zero (b) more than either one (c) their sum (d) less than either one
22. 22.What does a fuse do? (a) makes a beeping sound (b) is a resistance knob (c) smooths a wobbly supply (d) blows if current is high
23. 23.🔺 A current of 2.5 A flows through a 12 Ω resistor. What is the voltage across it (in volts)? =
24. 24.🔺 In the V-I-R triangle, how do we find V? (a) V = I × R (b) V = R ÷ I (c) V = I ÷ R (d) V = I + R
25. 25.🔺 A current of 0.2 A flows when 1.6 V is joined across a resistor. What is its resistance (in ohms)?
26. 26.🧩 Which component limits the current? (a) fuse (b) diode (c) resistor (d) potentiometer
27. 27.🔺 A 12 V supply is joined across a 4 Ω resistor. What current flows (in amperes)? =
28. 28.🧾 A 500 W appliance runs for 6 hours. How many units (kWh) of electricity does it use? =
29. 29.True or false: power is measured in ohms (Ω). (a) True (b) False
30. 30.💡 What does LED stand for? (a) low energy device (b) large electric dial (c) light-emitting diode (d) light energy dial
31. 31.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) gets bigger (b) gets smaller (c) stays the same (d) becomes zero
32. 32.🌈 A gold fourth band on a resistor means the value may be off by … (a) 0 % (b) 25 % (c) 5 % (d) 50 %
33. 33.🌈 A resistor has the colour bands white, green, red. What is its value in kilo-ohms (kΩ)? =
34. 34.💡 A red LED (it uses 2 V) is joined with a 200 Ω resistor to a 4 V supply. What current flows (in mA)?
35. 35.🔍 Which is the odd one out? (a) use LED lamps (b) use daylight to read (c) run fans in empty rooms (d) set the AC to 24 °C
36. 36.💡 An LED is joined to a 9 V battery through a 220 Ω resistor; its long leg goes to the + side and its short leg to the − side. What happens? (a) lights up (b) does not light (c) may burn out
37. 37.🧮 Resistors of 68 Ω and 22 Ω are joined in series. What is the total resistance (in ohms)?
38. 38.📏 How many ohms (Ω) is 5.7 kΩ?
39. 39.🔺 A current of 0.2 A flows when 0.4 V is joined across a resistor. What is its resistance (in ohms)?
40. 40.🔺 A current of 40 mA flows through a 500 Ω resistor. What is the voltage across it (in volts)? =

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