Electrical Engineering - Energy and Power - Discussion

Discussion Forum : Energy and Power - General Questions (Q.No. 9)
9.
A 120 resistor must carry a maximum current of 25 mA. Its rating should be at least
4.8 W
150 mW
15 mW
480 mW
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
61 comments Page 3 of 7.

Supriyo said:   9 years ago
I too think 75mw is the correct answer.

Pratik suhas gajengi said:   9 years ago
You are right @R N Trimukhe.

Ravi ranjan said:   9 years ago
P=i2r bit here I is the RMS and irms =I'm/√2 now apply 25ma square * 120 * 2 = 150mw.

Rishipal said:   9 years ago
D is correct because maximum current is given it is not RMS current so, it changes in RMS current.

RMS current=maximum current/root2. Then power = i2r.

Sathish said:   1 decade ago
They are not that one is RMS value its 75 mW only.

S.Mohamed said:   9 years ago
Thanks @Pranav.

Yashmendr Tiwari said:   9 years ago
@All.

The concept of max and rms fundamental is not right bz max current already given
then why you are calculate Imax = Irms * sqrt2 = 25mA * sqrt2 = 0.0353?

Please explain me.

Bibek said:   8 years ago
I think 75 mW is the correct answer.

Sam said:   6 years ago
Yes it should be at least greater than the rated value.

Mustansar Zubair said:   3 months ago
P =VI
V = IR.
So,
P =I^2R.


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