If the electric potential of the inner metal sphere is $10$ $ volt$ $\&$ that of the outer shell is $5$ $volt$, then the potential at the centre will be ......$volt$

Two point charges $4\,\mu C$ and $ - 1\,\mu C$ are kept at a distance of $3\ m$ from each other. What is the electric potential at the point where the electric field is zero?......$V$

Variation in electric potential is maximum if one goes

In a uniform electric field, the potential is $10$ $V $ at the origin of coordinates, and $8$ $V$ at each of the points $(1, 0, 0), (0, 1, 0) $ and $(0, 0, 1)$. The potential at the point $(1, 1, 1)$ will be....$V$

Two tiny spheres carrying charges $1.5 \;\mu\, C$ and $2.5\; \mu\, C$ are located $30 \;cm$ apart. Find the potential and electric field

$(a)$ at the mid-point of the line joining the two charges, and

$(b)$ at a point $10\; cm$ from this midpoint in a plane normal to the line and passing through the mid-point.

Assume that an electric field $\vec E = 30{x^2}\hat i$ exists in space. Then the potential difference $V_A-V_O$ where $V_O$ is the potential at the origin and $V_A$ the potential at $x = 2\ m$ is....$V$