**Solution:**

Gravitational field due to a mass distribution is given by:
I=k/x^3 in the direction (k is const)

Let us consider a point mass 'M' at the origin.
Then, the gravitational potential due to this mass at a distance 'r' is given by:
V = -GM/r

We need to find the gravitational potential at a distance x/√2 from the origin.

**Step 1: Finding the gravitational field due to the point mass**

Let us find the gravitational field due to the point mass 'M' at a distance 'x' from the origin.
We know that the gravitational field due to a point mass is given by:
E = GM/x^2

Now, we can find the value of 'k' in terms of 'G' and 'M'.
We know that the gravitational field at a distance 'x' is given by:
I = k/x^3
Therefore, k = Ix^3

Substituting the value of 'k' in terms of 'I' and 'x' in the expression for gravitational field due to a point mass, we get:
E = GMI/x^5

**Step 2: Finding the gravitational potential due to the mass distribution**

We can use the concept of superposition to find the gravitational potential due to the mass distribution.
Let us divide the mass distribution into small point masses of mass 'dm'.
Then, the gravitational potential due to each point mass at a distance 'x' is given by:
dV = -Gdm/x

The total gravitational potential due to the mass distribution is given by:
V = ∫ dV

Integrating both sides with respect to 'dm', we get:
V = -G ∫ (dm/x)

Now, we need to express 'dm' in terms of the mass distribution.
We know that the mass of the mass distribution is given by:
M = ∫ dm

Therefore, dm = M(dx/L)^3, where 'L' is the total length of the mass distribution.
Substituting the value of 'dm' in the expression for gravitational potential, we get:
V = -GM ∫ (dx/x^3)

Integrating both sides, we get:
V = GM/x

Therefore, the gravitational potential due to the mass distribution is given by:
V = GM/x

**Step 3: Finding the gravitational potential at a distance x/√2**

We need to find the gravitational potential at a distance x/√2 from the origin.
Therefore, we need to substitute 'r' with 'x/√2' in the expression for gravitational potential due to a point mass.
We get:
V = -GM/(x/√2)

Simplifying, we get:
V = -√2 GM/x

Therefore, the gravitational potential at a distance x/√2 from the origin is -√2 GM/x.