Electronics Worksheet: Components and Ohm’s Law Test

Electronics lesson 20: Part 2 test: components and Ohm’s law · Set 377 · 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.🔺 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
2. 2.🧮 Two resistors in parallel give a total that is … (a) their sum (b) more than either one (c) always zero (d) less than either one
3. 3.💡 On an LED, is the leg by the flat edge the anode (+) or the cathode (−)? (a) cathode (−) (b) anode (+)
4. 4.🌈 A resistor has the colour bands green, violet, red. What is its value (in ohms)?
5. 5.⚡ A device works on 3 V and takes 0.1 A. What is its power (in watts)? =
6. 6.🌈 A gold fourth band on a resistor means the value may be off by … (a) 25 % (b) 5 % (c) 50 % (d) 0 %
7. 7.💡 On an LED, is the shorter leg the anode (+) or the cathode (−)? (a) anode (+) (b) cathode (−)
8. 8.🧾 A family uses 170 units of electricity in a month and each unit costs ₹4. What is the bill (in ₹)?
9. 9.🧩 Which component glows using little power? (a) capacitor (b) transistor (c) fuse (d) LED
10. 10.💡 Does it save or waste electricity to unplug idle chargers? (a) wastes electricity (b) saves electricity
11. 11.📏 Voltmeter or ammeter: which one measures voltage? (a) ammeter (b) voltmeter
12. 12.🔺 A current of 1.5 A flows when 15 V is joined across a resistor. What is its resistance (in ohms)?
13. 13.🌈 A resistor has the colour bands red, grey, brown. What is its value (in ohms)?
14. 14.True or false: the voltmeter measures voltage. (a) False (b) True
15. 15.🔺 A current of 40 mA flows through a 470 Ω resistor. What is the voltage across it (in volts)? =
16. 16.🧮 Adding another resistor in series makes the total resistance … (a) stay the same (b) zero (c) bigger (d) smaller
17. 17.🔺 A current of 25 mA flows through a 150 Ω resistor. What is the voltage across it (in volts)? =
18. 18.🔺 A 2 V supply is joined across an 8 Ω resistor. What current flows (in amperes)? =
19. 19.🌈 A resistor has the colour bands violet, black, orange. What is its value in kilo-ohms (kΩ)? =
20. 20.Which of these is measured in watts (W)? (a) energy used each second (b) the push of a cell (c) current (d) the flow of charge
21. 21.🌈 A resistor has the colour bands brown, blue, red. What is its value (in ohms)?
22. 22.🔺 A current of 50 mA flows when 6 V is joined across a resistor. What is its resistance (in ohms)?
23. 23.🔺 A 2.4 V supply is joined across a 12 Ω resistor. What current flows (in amperes)? =
24. 24.True or false: the flow of charge is measured in amperes (A). (a) True (b) False
25. 25.🔺 A current of 2.5 A flows through a 4 Ω resistor. What is the voltage across it (in volts)? =
26. 26.🧩 Which component smooths a wobbly supply? (a) resistor (b) LDR (c) motor (d) capacitor
27. 27.🌈 A resistor has the colour bands white, red, red. What is its value in kilo-ohms (kΩ)? =
28. 28.🧾 A 100 W appliance runs for 2 hours. How many units (kWh) of electricity does it use? =
29. 29.🔺 A current of 3 A flows through a 20 Ω resistor. What is the voltage across it (in volts)? =
30. 30.Which of these is measured in ohms (Ω)? (a) energy used each second (b) power (c) how much a part resists (d) current
31. 31.🔺 A current of 40 mA flows through a 200 Ω resistor. What is the voltage across it (in volts)? =
32. 32.💡 A red LED (it uses 2 V) is joined with a 200 Ω resistor to a 3 V supply. What current flows (in mA)?
33. 33.What does a capacitor do? (a) blows if current is high (b) smooths a wobbly supply (c) turns a fan or wheels (d) has coloured bands
34. 34.🔺 A current of 10 mA flows through a 100 Ω resistor. What is the voltage across it (in volts)? =
35. 35.🔺 A current of 50 mA flows when 25 V is joined across a resistor. What is its resistance (in ohms)?
36. 36.🔺 The voltage stays the same and the resistance gets bigger. The current … (a) stays the same (b) gets bigger (c) becomes zero (d) gets smaller
37. 37.🧩 Which component stores a little charge? (a) capacitor (b) motor (c) LDR (d) potentiometer
38. 38.📏 How many ohms (Ω) is 5.6 kΩ?
39. 39.🌈 Which colour bands (1st digit, 2nd digit, multiplier) mark an 84000 Ω resistor? (a) yellow-grey-orange (b) grey-yellow-yellow (c) grey-yellow-red (d) grey-yellow-orange
40. 40.⚡ A device works on 1.5 V and takes 1.5 A. What is its power (in watts)? =

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