# The density of core of a planet is #rho_1# and that of outer shell is #rho_2#. The radius of core is R and that of planet is 2R. Gravitational field at outer surface of planet is same as at the surface of core what is the ratio #rho/rho_2#. ?

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(1)3/4

(2)5/3

(3)7/3

(4)3/5

(1)3/4

(2)5/3

(3)7/3

(4)3/5

##### 1 Answer

Mar 15, 2018

#### Explanation:

Suppose, mass of the core of the planet is

So,field on the surface of core is

And,on the surface of the shell it will be

Given,both are equal,

so,

or,

or,

Now,

and,

Hence,

So,

or,