question_answer

The ratio of the weights of a body on the Earth's surface to that on the surface of a planet is 9 : 4. The mass of the planet is th of that of the Earth. If 'R' is the radius of the Earth, what is the radius of the planet ? (Take the planets to have the same mass density)                                                                                                        [JEE Main 12-4-2019 Afternoon]

A)                        

B)     

C)                         D)      Correct Answer: B Solution : [b] Since mass of the object remains same

Weight of object will be proportional to 'g'

(acceleration due to gravity)

Given

Also, (M is mass planet, G is universal gravitational constant, R is radius of

planet)