Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 930 · 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.🧮 Adding another resistor in series makes the total resistance … (a) smaller (b) zero (c) bigger (d) stay the same
2. 2.True or false: on an LED, the longer leg is the anode (+). (a) True (b) False
3. 3.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
4. 4.🌈 In the resistor colour code, which number does black stand for?
5. 5.Which of these is measured in volts (V)? (a) resistance (b) how much a part resists (c) the flow of charge (d) voltage
6. 6.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) stays the same (b) becomes zero (c) gets smaller (d) gets bigger
7. 7.🧮 Resistors of 150 Ω and 20 Ω are joined in series. What is the total resistance (in ohms)?
8. 8.Which of these is measured in watts (W)? (a) how much a part resists (b) the flow of charge (c) power (d) resistance
9. 9.⚡ A 5 W device works on 5 V. What current does it take (in amperes)? =
10. 10.🔺 A current of 40 mA flows through a 400 Ω resistor. What is the voltage across it (in volts)? =
11. 11.What does a capacitor do? (a) glows using little power (b) smooths a wobbly supply (c) limits the current (d) turns a fan or wheels
12. 12.🔺 A 5 V supply is joined across a 500 Ω resistor. What current flows (in milliamperes, mA)?
13. 13.True or false: to leave fridge door open saves electricity. (a) True (b) False
14. 14.True or false: on an LED, the leg by the flat edge is the anode (+). (a) False (b) True
15. 15.⚡ Power tells us … (a) energy used each second (b) the colour of light (c) the size of a cell (d) the length of a wire
16. 16.💡 A red LED (it uses 2 V) is joined with a 150 Ω resistor to a 5 V supply. What current flows (in mA)?
17. 17.🧮 Resistors of 50 Ω, 470 Ω, 68 Ω and 150 Ω are joined in series. What is the total resistance (in ohms)?
18. 18.📏 In the water-pipe picture of a circuit, voltage is like … (a) the tap handle (b) the water tank lid (c) the water pressure (d) the pipe colour
19. 19.🔺 A current of 0.5 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
20. 20.🧩 Which component makes a beeping sound? (a) LED (b) motor (c) LDR (d) buzzer
21. 21.🔺 In the V-I-R triangle, how do we find R? (a) R = V ÷ I (b) R = V + I (c) R = I ÷ V (d) R = V × I
22. 22.🔺 A current of 10 mA flows when 2.2 V is joined across a resistor. What is its resistance (in ohms)?
23. 23.🔺 A current of 40 mA flows through a 250 Ω resistor. What is the voltage across it (in volts)? =
24. 24.What does a motor do? (a) boosts a small signal (b) turns a fan or wheels (c) limits the current (d) smooths a wobbly supply
25. 25.What does a transistor do? (a) makes things spin (b) limits the current (c) smooths a wobbly supply (d) boosts a small signal
26. 26.⚡ A device works on 6 V and takes 1.5 A. What is its power (in watts)? =
27. 27.True or false: the voltmeter is joined across a part. (a) True (b) False
28. 28.True or false: the ammeter is joined across a part. (a) False (b) True
29. 29.🌈 A resistor has the colour bands blue, grey, brown. What is its value (in ohms)?
30. 30.🧮 A 3.25 V battery is joined to 3 Ω and 10 Ω resistors in series. What current flows (in amperes)? =
31. 31.🧾 A family uses 70 units of electricity in a month and each unit costs ₹6. What is the bill (in ₹)?
32. 32.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 69 Ω resistor? (a) blue-white-black (b) white-blue-black (c) blue-white-brown (d) violet-white-black
33. 33.🔍 Which is the odd one out? (a) leave the TV on standby (b) set the AC to 24 °C (c) unplug idle chargers (d) use LED lamps
34. 34.💡 Does it save or waste electricity to set the AC to 24 °C? (a) wastes electricity (b) saves electricity
35. 35.🔺 A current of 10 mA flows when 4.7 V is joined across a resistor. What is its resistance (in ohms)?
36. 36.💡 Does it save or waste electricity to close the fridge quickly? (a) wastes electricity (b) saves electricity
37. 37.📏 How many ohms (Ω) is 2 kΩ?
38. 38.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark a 14 Ω resistor? (a) yellow-brown-black (b) brown-yellow-black (c) brown-yellow-brown (d) red-yellow-black
39. 39.💡 Does it save or waste electricity to use LED lamps? (a) saves electricity (b) wastes electricity
40. 40.True or false: to run fans in empty rooms wastes electricity. (a) True (b) False

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