A disk of radius `a//4` having a uniformly distributed charge 6 C is placed in the xy plane with its center at `(-a//2,0,0)`. A rod of length carrying a uniformly distributed charge 8 C is placed on the x-axis from `x = a//4 to x = 5a//4`. Two point charges `-7C and 3C` are placed at `(a//4,-a//4,0) and (-3a//4,3a//4,0)`, respectively. Consider a cubical surface formed by six surfaces `x = +-a//2, y = +-a//2, z = +-a//2`. The electric flux through this cubical surface is

Options

A. `(-2C)/in_(0)`
B. `(2C)/in_(0)`
C. `(10C)/in_(0)`
D. `(12C)/in_(0)`

Answer

A

Explanation

`phi=q_("inclosed")/in_(0)`
`phi=(-2C)/in_(0)`