Question

1)

The current in the conductor varies over time as shown in the figure. How much charge passes through a cross section of the conductor in the time interval t = 0s to t = 4s? Answer in units of C

2)

3)

4)

Help ASAP. will choose best answer quickly.

Answer 1

1). current = dq/dt

so Q= idt

so current passed during this time = area under the curve fro t=0 to t= 4s

so

charge transfereed=2*1+1/2*4*1+6*1.5+1/2*.5*4

= 14 Coulomb

b). i*4= 14

so i= 14/4

= 3.5 A

2). resistance of 9.77 cm of copper wire is R= rho*L/A

=1.68*10^-8*9.77*10^-2/[3.14*(1.35/2)^2*10^-4]

=1.1472*10^-5 ohm

so voltage difference= iR

=61*R

= 6.998*10^-4 V

=699.8 u V

3).dR = ?*dr/(2*?*r*L)

Integrate

?dR = ?/(2*?*L) * ?(1/r)*dr

R = ?/(2*?*L) * ln(r) [r = ra to rb)

R = ?/(2*?*L) * [ln(rb) - ln(ra)]

R = ?/(2*?*L) * ln(rb/ra)

R=3.9*10^5/(2*3.14*0.03)*ln(1.19/0.31)

R=2.78 Mohm

4).ner resistance is R= Ro(1-5*10^-4*(91-16)

Ro= 141

so R=135.72

so I= Vo/R

= 4.8/135.72

=0.0353688 A

= 35.368 mA

7). I= V/R

=16/39=0.41 A

8)n= i*t/1.6*10^-19

= 0.41*16*60/1.6*10^-19

= 2.46*10^21 electrons