Page 82 - Engineering Mathematics Workbook_Final
P. 82

Vector Calculus

            188.   The flux of the vector filled                         (a) 2                (b) 4
                   F =  xi +  y j +  zk  flowing out through
                                                                         (c) 8                (d) 12
                   the surface of the ellipsoid
                    x 2  +  y 2  +  z 2  =        0                                                    [CSIR]
                    a 2  b 2   c 2  1. a b c   is


                                             
                      
                   (a)  abc              (b) 3 abc                192.   The surface integral     F   n ds
                                                                                               S
                   (c) 2 abc            (d) 4 abc                      over the surface S of the sphere
                                                                                2
                                                                           2
                                                                                     2
            189.   The value of                                          x +   y +  z =  9 , where
                                                  )
                                 )
                                                                                     ) (x z j +
                      S   ( (  x −  yz i −  2x y j +  zk   n ds        F =  (x +  y i +    +  )    ( y +  ) z k
                                                      $
                           3
                                         2
                    where S is the surface of the cube                   and n is the unit outward surface normal,
                                            2
                                        z
                                    y
                   bounded by  x = = =  and co-                          yields _____.
                   ordinate planes is ________                                                  [GATE-17-ME]
                       32                   56                    193.   Let a > 0 and let
                   (a)                   (b)
                                                                                            3
                       3                     3                           S =   (   x , , y  ) z  R x +  y +  z =  a 2 
                                                                                               2
                                                                                                     2
                                                                                                          2
                                                                                                        )
                                                                                                       4
                       16                    64                          . Evaluate    S   ( x +  4  y +  4  z ds .
                   (c)                   (d)
                       3                     3
                                                                                                     
                                                                              
                                                                             2 a  6               12 a  4
                                        2
                                             2
                                                  2
            190.   Let S be the sphere  x +  y +  z = 1.                 (a)                   (b)
                                                                               5                     5
                   The value of surface integral
                                                                                                     
                                                                               
                                                                            12 a   8              12 a  6
               ( sin ,cos x ,2z z  sin y   ) ( , , y z ds  is         (c)                   (d)
                                                   )
                            2
                                  −
                       y
                  x
                                              x
              S                                                                 5                    5
                   _______                                                                          1  $
                                            2                   194.   Consider the function  F =  r 2  r , where
                   (a)                   (b)
                       3                      3                          r is distance from the origin and r  is the
                                                                                                         $
                       4                   8                           unit vector in the radial direction. The
                   (c)                   (d)                             divergence of this function over a sphere
                        3                    3                           of radius1, which includes the origin is
                                                                         _____.
            191.   Let S be the unit sphere
                     2
                    x +  y +  z =  1. Then the value of                  (a) 0                 (b) 2
                          2
                                2
                   surface integral                                      (c) 4                (d)  R
                                      )
                       S       (   2x +  3x −  y +  5z   2    ds  is
                               2
                                           2

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