A very long uniform line of charge has charge per unit length 4.74 ? C/m and lie
ID: 2287500 • Letter: A
Question
A very long uniform line of charge has charge per unit length 4.74?C/m and lies along the x-axis. A second long uniform line of charge has charge per unit length -2.46?C/m and is parallel to the x-axis at y1 = 0.404m .
What is the magnitude of the net electric field at point y2 = 0.218m on the y-axis?
What is the direction of the net electric field at point y2 = 0.218m on the y-axis?
What is the magnitude of the net electric field at point y3 = 0.620m on the y-axis?
What is the direction of the net electric field at point y3 = 0.620m on the y-axis?
Explanation / Answer
A line of charge having charge per unit length=p1= 4.74 uC/m lies along the x-axis.
A second line of charge has charge per unit length=p2= -2.46 uC/m and is parallel to the x-axis at y1= 0.404m .
point y2= 0.218 m on the y-axis
y2 is between the lines.As one is +ive and the other is - ive, the field will be added up,it will be towards second -ive line
E =2k[ p1/r1 + p2/r2 ]
E =2*9*10^9[ 4.74 *10^-6/0.218 +2.46 *10^-6 /0.186 ]
E =18*10^3[ 4.74 /0.218 +2.46 /0.186 ]
E =18*10^3[ 34.968 ]
E =6.294*10^5 N/C
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2-)The direction of the net electric field at point y2= 0.218m on the y-axis is along +y-axis
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3-) point y3= 0.620m on the y-axis
At y3, the field are in opposite direction, the field due to positive is less than field due to negative
Total field will be difference of two fields
E =2k[ p1/r1 - p2/r2 ]
E =18*10^3[ 4.74 /0.620 - 2.46 /0.216 ]
E = -18*10^3[ 3.74]
E = 6.7*10^4 N/C
3-) the magnitude of the net electric field at point y3= 0.620m on the y-axis is 6.7*10^4 N/C
4-) The direction of the net electric field at point y3 = 0.620m on the y-axis is -y-axis