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
resistor must carry a maximum current of 25 mA. Its rating should be at leastDiscussion:
59 comments Page 3 of 6.
THE MAN said:
1 decade ago
Rating of any device is such that it should carry current up to twice of the capacity. May be this reason so answer is doubled.
Rohit kumar said:
1 decade ago
P = i^2*R.
So that,
P = 25^2*120 = 25*25*120*(10^-3) = 75mW.
But is not exist so that what right answer of that question.
So that,
P = 25^2*120 = 25*25*120*(10^-3) = 75mW.
But is not exist so that what right answer of that question.
Sweta said:
1 decade ago
P = I^2*R.
P = (Imax)^2 * R.
P = (Irms*sqrt(2))^2*R.
P = (0.025*sqrt(2))^2* 120.
P = (0.035355)^2 *120.
P = 150mW.
P = (Imax)^2 * R.
P = (Irms*sqrt(2))^2*R.
P = (0.025*sqrt(2))^2* 120.
P = (0.035355)^2 *120.
P = 150mW.
(1)
Rojohn Ogalinola said:
7 years ago
Use a resistor rated for at least 2 times the required power dissipation.
Thus,
P=(25mA)^2 x 2(120ohm) = 150mW.
Thus,
P=(25mA)^2 x 2(120ohm) = 150mW.
(1)
Eric said:
1 decade ago
p= i2r or p=vi so v=ir =25/1000 * 120=3v
p=vi =3*0.025 = 0.075= 75mv
OR
P=I2R =0.025Square *120 = 75mv
p=vi =3*0.025 = 0.075= 75mv
OR
P=I2R =0.025Square *120 = 75mv
James said:
1 decade ago
75mw is correct but rating is alwaya more, so 150mw which is nerest to 75mw according to option is correct.
Rabi Sankar Samanta said:
1 decade ago
p = I2R (25mA=0.025A).
P = 0.025*0.025*120.
P = 0.075W.
P = 75 mW.
Answer did not maching.
P = 0.025*0.025*120.
P = 0.075W.
P = 75 mW.
Answer did not maching.
R n trimukhe said:
1 decade ago
Simply go through ohms law,
V = IR.
V = 25*10-3*120.
V = 3 v.
P=VI.
P=3*25*10-3.
P=75 mWatt.
V = IR.
V = 25*10-3*120.
V = 3 v.
P=VI.
P=3*25*10-3.
P=75 mWatt.
Ravi ranjan said:
8 years ago
P=i2r bit here I is the RMS and irms =I'm/√2 now apply 25ma square * 120 * 2 = 150mw.
Prakash said:
1 decade ago
p= 25*1.414*25*1.414*120*10*-3= 150mw
Vrms = Vm/1.414=25
its given in rms so convert vmax.
Vrms = Vm/1.414=25
its given in rms so convert vmax.
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