Gravitational field of a body is the space around it within which its gravitational force of attraction is perceptible. **Strength of Gravitational Field (Gravitational intensity):** Gravitational intensity at a point in the field due to a body is the force experienced by a unit mass placed at that point. It is denoted by ‘E’. It is a vector quantity. Expressing in algebraic symbols, \(E = \frac{F}{m}\), F being the force experienced by the mass ‘m’ in the gravitational field. But \(F = -G\frac{Mm}{r^2}\)(here, ‘-’ sign indicates that gravitational force is an attractive force.) \(\therefore E = -\frac{\frac{GMm}{r^2}}{m}\) \(\implies E = -\frac{GM}{r^2}\)