Question: 15: A body of mass 60 g experiences a gravitational force of 3.0 N , when placed at a particular point. The magnitude of the gravitational field intensity at that point is
(1) 20 \mathrm{~N} / \mathrm{kg}
(2) 180 \mathrm{~N} / \mathrm{kg}
(3) 0.05 \mathrm{~N} / \mathrm{kg}
(4) 50 \mathrm{~N} / \mathrm{kg}
Answer: Option (4)
Explanation:
The gravitational field intensity g at a point is defined as the gravitational force experienced per unit mass at that point.
Mathematically, it is given by
g = \frac{F}{m},
where F is the gravitational force and m is the mass of the body.
The mass of the body is given as 60 g, which in kilogram is
m = 60 \times 10^{-3} = 0.06 \ \mathrm{kg}.
The gravitational force acting on the body is F = 3.0 \ \mathrm{N}.
Substituting the values in the formula,
g = \frac{3.0}{0.06}.
g = 50 \ \mathrm{N \, kg^{-1}}.
Thus, the magnitude of the gravitational field intensity at that point is
50 \ \mathrm{N} / \mathrm{kg}.