Question

two charges of value 2c and -50c are placed 80cm apart. calculate the distance of the point from the smaller charge where the intensity is zero

Answer 1

Hi friend answer this question

Answer 2

hello friend...!!

according to the given question,

the both the charges are opposite in nature hence we can say that the resultant intensity will be the same of at the point joining the charges . 

assume the positive charge to be at the orgin and the negative charge to be at the right side of the orgin along the positive x axis at a distance of 0.8 m 

now,

E1 = K ( 2 X 10⁻⁶ ) / ( r  + 0.80)²

E2 = K ( 50 x 10⁻⁶) / r² 

we know that 

E1 = E2 

implies,

1/ ( 0.08 + r ) ² = 25 / r²

implies,

r² = 25 ( 0.08 + r ) ²

by solving we get ,

24r² + 40 r + 16 = 0 

therefore,

r = -1 and r = - 0.66 

therefore the answer is -1

the other answer cannot be considered because it represents the point between the charges where the magnitude are the same . the net field is not  zero there .

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hope it helps...!!