HomeLearn Fast select Course
Show Unit/ChapterChange UnitChange SubjectLast Menu
NEET-XII-Physics

pp year:2018

with Solutions -
Qstn# 10 Prvs-QstnNext-Qstn
  • #10
    Two wires are made of the same material
    and have the same volume. The first wire
    has cross-sectional area A and the second
    wire has cross-sectional area 3A. If the
    length of the first wire is increased by
    ``\triangle l`` on applying a force F,
    how much force is needed to stretch the
    second wire by the same amount ?
    (1) 9F
    (2) 6F
    (3) 4F
    (4) F
    digAnsr:   1
    Ans : (1)
    Sol. =
    ▵


    F
    Y
    A
     V = A so =
    V
    A
    ▵ ▵
    = =
     

    2YA YA
    F
    V
     
    =  
     
    2
    1 1
    2 2
    F A
    F A &implies;
     
    = = 
     
    2
    2
    F A 1
    F 3A 9
    F2 = 9F