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If a section of wire with resistance R is evenly elongated to twice the original, the resistance value is () A.2R B.1/2R C.4R D.1/4R With instructions, thank you!
Are you in junior high school or high school?
Remember this formula:
R＝ρL/S
L is the length of the conductor
S is the cross-sectional area of the conductor
ρ is the resistivity of conductor. The resistivity of each kind of conductor is different. When l and s are the same, the greater the ρ, the greater the resistance
－－－－－
Choose C
Because the volume of the conductor remains unchanged, the length becomes twice of the original and the cross-sectional area becomes the original
R＝ρ2L/½S＝4ρLS
So choose C
How many ohms is the resistance of a copper wire used in the experiment?
The physical default is zero because the length is short and the resistance of copper is low
After a wire with a resistance value of 5 ohm is elongated, what is the resistance of the wire at this time
The specific data of resistance after lengthening can not be determined, but it can be determined that the resistance will certainly increase, because the longer the wire length is, the greater the resistance will be, the smaller the cross-sectional area will be, and the greater the resistance will be. However, lengthening the wire will increase the length and reduce the cross-sectional area, so the resistance will increase, which is greater than 5
There is a wire with a resistance of 4 ohm. If you lengthen it to twice the original resistance, what is the resistance
Note: the volume of the wire remains unchanged! When the length of the wire changes by 2 times, the cross-sectional area changes by 1 / 2 of the original. Considering the influence of two factors, if the resistance changes by 4 times, it is: 16 ohm. In addition, a formula of resistance law that has been deleted from the physics textbook is: r = PL / s
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