# Electronics - Resistance and Power - Discussion

### Discussion :: Resistance and Power - General Questions (Q.No.5)

5.

With 1 mA of current, what wattage rating should a 470 ohm resistor have?

 [A]. 1/4 watt [B]. 1/2 watt [C]. 1 watt [D]. 2 watts

Explanation:

No answer description available for this question.

 Manikanta said: (Apr 19, 2012) P=I^2R, So P = 1*10^-6*470 = 0.00047W. How will come 1/4. Please explain?

 Rathi said: (Apr 19, 2012) @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.

 Domy Dimal said: (Oct 22, 2014) 0.25 w is greater than 0.00047w. Then how?

 Theophillus said: (May 7, 2015) I don't understand how did you get 0.25 W there seriously.

 Vasava said: (Aug 31, 2015) I can't understand how it come 0.25 watt?

 Priyank Sharma said: (Jun 2, 2016) Why its answer is 0.25watt?

 A.Sathish said: (Jun 29, 2016) 0.00047w is correct, which is the nearest value.

 Lewis said: (Aug 19, 2016) On our resistor wattage we have 1/8W, 1/4W, 1/2W, 1W,2W so when we rate we take the closest to 0.00047W which is the 0.25W. If there was the 0.125 W(1/8) resistor would be more suitable.

 Fred Simz Jr said: (Feb 9, 2017) I can't understand how 0.25w came? Please explain.

 Vignesh said: (Apr 11, 2017) Here, the m value is 10^-3 then how to get the answer 1/4?

 Soni said: (Sep 16, 2017) P= IV, P=I*I*R. 1*10^-3*10^-3*470, =0.00047w.

 Engr Faizan Rais said: (Sep 28, 2018) p=i^2*R. So putting the values: p = (40mA)^2*470 p = 0.751W So, 0.751 w is nearer value to 1 w, the ans is 1 watt.

 Gopal said: (Sep 17, 2019) I am not getting the solution. Please explain it.

 Gopala said: (Sep 17, 2019) Explain how it come 1/4?

 Rajesh said: (Oct 4, 2019) 0.00047 less than 1/4 watt so least one is 1/4 watt is right answer. 1000mW = 1W, 0.250W is correct.

 Thea said: (Apr 11, 2020) 1/4 watts, 1/2 watts or 1 watts means the physical size of the resistor and not the technical measures. 1/4 watts means the resistor physical size is smaller. This usually uses in experiments or another device that handle a small amount of power. And 1 watt means the physical size of the resistor is bigger and usually use in high power use to be not destroyed immediately by the current flowing.