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show all steps please Two 1.9-cm-diameter disk face each other, 2.2 mm apart. Th

ID: 1537372 • Letter: S

Question

show all steps please

Two 1.9-cm-diameter disk face each other, 2.2 mm apart. They are changed to plusminus 16 nC. What is the electric field strength at the midpoint between the centers of the disks? Express your answer to two significant figures and include the appropriate units. A proton is shot from the center of the negative disk toward the center of the positive disk. What launch speed must the proton have to just barely reach the positive disk? Express your answer to two significant figures and include the appropriate units.

Explanation / Answer


the potential of the capacitor is V = E*d = 4.1*10^5*1.6*10^-3 V = 656 V


  
the electron gains energy which is equal to q*V


that is 0.5*mv1^2 - 0.5*mv2^2 = q*V

m mass of electron = 9.1*10^-31 kg, q = -1.6*10^-19 C


   0.5mv1^2 = 0.5*mv2^2 - q*V

Given

diameterof the disls d = 1.9 cm, radius r = 0.95 cm = 0.0095m

sseparation of the disks s = 2.2mm = 2.2*10^-3m


charge q = 16 nC

from part A E = 5.64*10^8 N/C

when a proton shot from centre of the +ve disk to the centre of the -ve disk


   the proton gains energy from q*V = change in k.e , proton should barely reach -ve disk


   Potential V = E*d = 5.64*10^8*(2*0.0095+2.2*10^-3) V = 11956800 V

now q*v = 11956800*1.6*10^-19 J= 1.913088*10^-12 J

which is equal to the kientic energy of the proton = 0.5*mv^2


           ==> v = sqrt(2*1.913088*10^-12/(1.67*10^-27)) m/s
           = 47865680.33 m/s