Question

$\text{The flux density at a point in space is given by}\overrightarrow{B}\text{=}4x{\hat{a}}_x\text{+}2ky{\hat{a}}_y\text{+}8{\hat{a}}_{z}Wb/m^2.$
The value of constant k must be equal to

• A.
  -2
• B.
  -0.5
• C.
  +0.5
• D.
  +2

Answer 1

The correct option is A

-2
Ans :(a)

$▽.\overrightarrow{B}=(\frac{\partial }{\partial x}{a}_x+\frac{\partial }{\partial y}{a}_y+\frac{\partial }{\partial z}{a}_z).(4x{a}_x+2ky{a}_y+8a_z)=0$
or $4+2k=0$
$k=-2$