Question

If the radius of the earth were to shrink by $$1\% ,$$  with its mass remaining the same, the acceleration due to gravity on the earth’s surface would

A. decrease by $$1\% $$
B. decrease by $$2\% $$
C. increase by $$1\% $$
D. increase by $$2\% $$  
Answer :   increase by $$2\% $$
Solution :
$${\text{As}}\,\,g = \frac{{{\text{ }}GM{\text{ }}}}{{{R^2}}}$$
when radius is reduced by $$1\% $$  then
$$\eqalign{ & R' = R - \frac{R}{{100}} = .99\,R, \cr & {\text{so,}}\,g' = \frac{{GM}}{{{{\left( {.99\,R} \right)}^2}}} = 1.02\frac{{GM}}{{{R^2}}} \cr & \Rightarrow \% \,{\text{increase}}\, = 2\% \cr} $$

Releted MCQ Question on
Basic Physics >> Gravitation

Releted Question 1

If the radius of the earth were to shrink by one percent, its mass remaining the same, the acceleration due to gravity on the earth’s surface would-

A. Decrease
B. Remain unchanged
C. Increase
D. Be zero
Releted Question 2

If $$g$$ is the acceleration due to gravity on the earth’s surface, the gain in the potential energy of an object of mass $$m$$ raised from the surface of the earth to a height equal to the radius $$R$$ of the earth, is-

A. $$\frac{1}{2}\,mgR$$
B. $$2\,mgR$$
C. $$mgR$$
D. $$\frac{1}{4}mgR$$
Releted Question 3

If the distance between the earth and the sun were half its present value, the number of days in a year would have been-

A. $$64.5$$
B. $$129$$
C. $$182.5$$
D. $$730$$
Releted Question 4

A geo-stationary satellite orbits around the earth in a circular orbit of radius $$36,000 \,km.$$   Then, the time period of a spy satellite orbiting a few hundred km above the earth's surface $$\left( {{R_{earth}} = 6400\,km} \right)$$    will approximately be-

A. $$\frac{1}{2}\,hr$$
B. $$1 \,hr$$
C. $$2 \,hr$$
D. $$4 \,hr$$

Practice More Releted MCQ Question on
Gravitation


Practice More MCQ Question on Physics Section