The strength of an electric field decreases with the square of the distance from the source charge. This means that if the distance from the source charge is doubled, the strength of the electric field will be reduced to one-fourth of its original value. Similarly, if the distance is tripled, the strength of the electric field will be reduced to one-ninth of its original value.

This relationship can be expressed mathematically as follows:

```

E = k * Q / r^2

```

where:

* E is the strength of the electric field in volts per meter (V/m)

* k is the electrostatic constant (8.988 × 10^9 N m^2/C^2)

* Q is the magnitude of the source charge in coulombs (C)

* r is the distance from the source charge in meters (m)

As can be seen from the equation, the strength of the electric field is inversely proportional to the square of the distance from the source charge. This means that the farther away from the source charge you get, the weaker the electric field will be.