The acceleration due to gravity ($g$) on the surface of the Earth is given by the formula $g = \frac{GM}{R^2}$, where $G$ is the universal gravitational constant, $M$ is the mass of the Earth, and $R$ is the radius of the Earth. The mass of the Sun does not appear in this expression for $g$ on Earth.

If $G$ becomes $10G$, the new acceleration due to gravity $g'$ becomes: $g' = \frac{(10G)M}{R^2} = 10 \left( \frac{GM}{R^2} \right) = 10g$.

Since $g$ increases by a factor of 10, the following changes occur:

1. Raindrops: They fall with higher acceleration ($10g$), so they drop faster. (Statement 1 is correct).
2. Walking: The weight of a body ($W = mg$) becomes $10$ times larger. Supporting and moving this increased weight makes walking more difficult. (Statement 2 is correct).
3. Pendulum: The time period of a simple pendulum is $T = 2\pi\sqrt{\frac{l}{g}}$. Since $g$ increases, $T$ decreases. (Statement 3 is correct).
4. Change in g: As calculated, $g$ changes from $g$ to $10g$. Therefore, the statement that $g$ would not change is incorrect.