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NEET-XII-Physics

P1 year:2019

with Solutions - page 4
Qstn# 37 Prvs-QstnNext-Qstn
  • #37
    Two point charges A and B, having charges +Q
    and -Q respectively, are placed at certain
    distance apart and force acting between them
    is F. If 25% charge of A is transferred to B,
    then force between the charges becomes :
    (1) F
    (2)``\frac {9F}{16}``
    (3)``\frac {16F}{9}``
    (4)``\frac {4F}{3}``
    digAnsr:   2
    Ans : ( 2 )
    Sol.
    A B
    r
    +Q -Q
    2
    2
    kQ
    F
    r
    =
    If 25% of charge of A transferred to B then
    =  = =  + =
    A B
    Q 3Q Q 3Q
    q Q and q Q
    4 4 4 4
    r
    q
    A
    q
    B
    A B
    1 2
    kq q
    F
    r
    =
    2
    1 2
    3Q
    k
    4
    F
    r
     
     
     =
    1 2
    9 kQ
    F
    16 r
    =
    1
    9F
    F
    16
    =