I need the answers for these problem ASAP 10. 011 points I Previous Answers SerP

Question

I need the answers for these problem ASAP

10. 011 points I Previous Answers SerPSE9 27 P015.MI.FB My Notes Ask Your Teacher A wire 50.0 m long and 2.00 mm in diameter is connected to a source with a potential difference of 9.11 V, and the current is found to be 2.60 A. Assume a temperature of 20.0°C and, using this table, identify the metal out of which the wire is made. Copper O gold O ron aluminum tungsten O platinum lead O silver Make sure you are conrectly calculating the resistance, and therefore the resistivity, from the given data. Need Help Read TIL It t Master

Explanation / Answer

A)

length l=50.0 m

diameter, d= 2.00 mm= 2*10-3 m   So radius r=d/2 = 1*10-3 m

potential difference V= 9.11 V

current = 2.60 A.

Temperature T= 20°C =20+273 Kelvin = 293 K

According to ohms law I=V/R           or   R=V/I =9.11/2.6 = 3.50

Resistance R= l/A   

where is resistivity of material,

A is area of cross section A = pi*r2 =3.14* (1*10-3)2

A= 3.14*10-6m2

rearranging   =RA/l = 3.5* (3.14*10-6)/50 = 2.2*10-8    m

From standard table, it matches with resistivity of silver

Silver

B)

Let

Resistance at 20 deg c = Ro

Resistance at 55 deg c, R1 = Ro [ 1 + t ]

= Ro [ 1 + ( 55 - 20 ) ]

= Ro [ 1 + 35 ]

Resistance at - 88 deg c, R2 = Ro [ 1 + ( - 88 - 20 ) ]

= Ro [ 1 - 108 ]

According to ohms law, I ( 1 / R )

I2 / I1 = R1 / R2

I2 / I1 = ( 1 + 35 ) / ( 1 - 108 )

I2 / I1 = ( 1 + 35 * 0.0039 ) / ( 1 - 108 * 0.0039 )

I2 / I1 = 1.1365 / 0.5788

I2 = 1.3 * ( 1.1365 / 0.5788 )

= 2.55 A

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