# ohms and power law

• May 1st 2007, 08:06 PM
rcmango
ohms and power law
find the resistance of an electric light bulb if there is a current of 0.8 A and a voltage potential difference of 120 V.

thankyou for any help with this one.
• May 1st 2007, 08:13 PM
Jhevon
Quote:

Originally Posted by rcmango
find the resistance of an electric light bulb if there is a current of 0.8 A and a voltage potential difference of 120 V.

thankyou for any help with this one.

we use ohm's law here, the equation is

V = IR

where V is the voltage, I is the current in amps and R is the resistance in ohms

=> R = V/I = 120/0.8 = 150 ohms
• May 2nd 2007, 03:33 AM
topsquark
Quote:

Originally Posted by Jhevon
we use ohm's law here, the equation is

V = IR

where V is the voltage, I is the current in amps and R is the resistance in ohms

=> R = V/I = 120/0.8 = 150 ohms

Again, since the unit is named for a person it needs to be capitalized, so the unit is "Ohms."

-Dan
• May 2nd 2007, 08:14 AM
Jhevon
Quote:

Originally Posted by topsquark
Again, since the unit is named for a person it needs to be capitalized, so the unit is "Ohms."

-Dan

My apologies again:) :)
• May 2nd 2007, 03:27 PM
rcmango
Thanks for the help on this one. Also, i'll be sure to use "Ohms in the future, also"
• May 5th 2009, 12:27 PM
unit764
Quote:

Originally Posted by topsquark
Again, since the unit is named for a person it needs to be capitalized, so the unit is "Ohms."

-Dan

I know this is a little old, but this is incorrect.

You may refer to section 5.2 of the SI brochure (http://www.bipm.org/utils/common/pdf...chure_8_en.pdf), which specifies that names of all units are treated as ordinary nouns and start with a lower-case letter even when the symbol for the unit begins with a capital letter. Section 5.1 states that the first letter of a symbol is capitalized only if it is derived from a proper name (for instance Hz for hertz), or to avoid confusion (for instance, litre is allowed to be represented by L since the lower-case el looks the numeral one).