If radius if earth is reduced to half without changing its mass, then match the following columns
`{:(,"Column-I",,"Column-II"),("(A)","Angular momentum of earth","(p)","Will become two times"),("(B)","Time period of rotation of earth","(q)","Will become four times"),("(C)","Rotational kinetic energy of earth","(r)","Will remain constant"),("(D)",,"(s)","None"):}`

Answer

`(A rarr q,B rarr s,c rarrq)`

Explanation

`L_(1)=I omega=(2)/(5)MR^(2)omega`
`L_(2)=(2)/(5)M((R)/(2))^(2)omega'`
As `L_(1)=L_(2)rArromega'=4 omega`
`:. (2pi)/(T')=4((2pi)/(T))rArr T=(T)/(4)`
Further, `K= (L^(2))/(2I)`
Since, angular momentum is constant and `I` has become (1/4)th. Therefore, kinetic energy will become 4 times.