Consider two solid spheres of radii R1=1m, R2=2m and masses M1 and M2, respectively. The gravitational field due to sphere (1) and (2) are shown. The value of M2M1 is:
(A)21
(B)31
(C)61✓ Correct
(D)32
Answer: (C)
Solution
The surface gravitational field of a uniform sphere is g=R2GM. From the graph, sphere 1 has surface field 2 and sphere 2 has surface field 3. For sphere 1, 2=12GM1 so GM1=2; for sphere 2, 3=22GM2 so GM2=12. The mass ratio is therefore M2M1=122=61.
JEE Main · 2020 · 08 Jan 2020 · Shift 1 · Single correct option