Choose the correct option.

If the mass of the earth is increased by 25% without any change in its size, then its acceleration due to gravity will _______________.

The acceleration due to gravity (g) on earth is given by:

 $g=\frac{GM}{R^2}$

G is the universal gravitational constant; M is the mass of the earth; R is the radius of the earth. 

From the above equation, we can observe that acceleration is directly proportional to the mass of the earth. 

g $\alpha$ M; 
Let us calculate the new acceleration due to gravity g₂ with the given new mass M₂. 

M₂ = $\frac{25}{100}$ M + M= 1.25 M

$\frac{g}{g_2}= \frac{M}{M_2}$

$\frac{g}{g_2}= \frac{M}{1.25M}$

$g_2= 1. 25 g$=$\frac{25}{100}g + g$= 25% g + g

So, if the mass of the earth is increased by 25 % and R is kept constant, the value of g will also increase by 25%.