Electronics - Resistance and Power - Discussion

Discussion Forum : Resistance and Power - General Questions (Q.No. 5)
5.
With 1 mA of current, what wattage rating should a 470 ohm resistor have?
1/4 watt
1/2 watt
1 watt
2 watts
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
16 comments Page 2 of 2.

Priyank sharma said:   9 years ago
Why its answer is 0.25watt?

Vasava said:   10 years ago
I can't understand how it come 0.25 watt?

Theophillus said:   1 decade ago
I don't understand how did you get 0.25 W there seriously.

Domy dimal said:   1 decade ago
0.25 w is greater than 0.00047w. Then how?

Rathi said:   1 decade ago
@Manikanta.
Yes you are right.
But we should take the wattage of the resistance greater than calculated value.
0.25(i.e 1/4) is greater than 0.00047W, So 1/4 is enough.
That means 1/4 watt is the right answer.

Note: If 1/8watt is given in option then 1/8 will be the correct answer.

Manikanta said:   1 decade ago
P=I^2R, So
P = 1*10^-6*470 = 0.00047W. How will come 1/4. Please explain?


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