A point charge `q_1` is placed inside cavity 1 and another point charge `q_2` is inside cavity 2. A point charge q is placed outside the conductor. For the situation described above, answer the following questions.
If the potential of the conductor is `V_0` and charge `q_2` is placed at the center of cavity 2, then potential at point Q is

Options

A. `q_2/(4piepsilon_0r'^2) + V_0`
B. `(q_2)/(4piepsilon_0)(1/r'_(2) + 1/r_(2)) + V_0`
C. `(q_2)/(4piepsilon_0)(1/r'_(2) - 1/r_(2)) + V_0`
D. `V_0`

Answer

C

Explanation

Potential at point Q `=` potential of conductor `+` potential due to `q_(2)+` potential due to `-q_(2)`
`=V_(0)+(q_(2))/(4piepsilon_(0)r_(2))=(q_(2))/(4piepsilon_(0))((1)/(r'_(2))-(1)/(r_(2)))+V_(0)`