NEET Exam Model Paper 8

A smooth block is released at rest from an inclined plane of inclination 45° and is allowed to slide a distance.′d′ Now same block is released on a similar rough inclined plane and allowed to slide the same distance. The time taken by block to slide on rough plane is ′n′ times the time taken by it on a smooth plane. Then whatwould be the coefficient of friction for the rough inclined plane?