Q1: Staggered rail joints are generally provided

ANS:A - on curves

Staggered rail joints are generally provided on curves because on the curves, the length of the outer rail is more than its inner length and if in this condition square joint is provided the outer rail tries to go out due to centrifugal force.

And because of this, the wheels of the train are not able to come together on the joint and the track remains intact.