Why is a cement floor laid in small pieces with gaps in between?

Why is the concrete floor made in small slabs, rather than a single block? Explain.

Why does a comb rubbed on hair attract small pieces of paper?

A long metal rod is bent to form a ring with a small gap if this is heated, will this gap increase or decrease?

Why is cement clinker obtained from rotary Kiln mixed with gypsum?

Why are villi present only in the small intestine?

A small piece of metal wire is dragged across the gap between the pole pieces of a magnet in 0.4 sec. If magnetic flux between the pole pieces is known to be 8 xx 10^(-4) Wb, then induced emf in the wire, is

A floor which measures 15mxx8m is to be laid with tiles measuring 50cmxx25cm . Find the number of tiles required. Further, if a carpet is laid on the floor so that a space of 1 m exists between its edges and the edges of the floor, what fraction of the floor is left uncovered.

A small piece of metal wire is dragged across the gap between the pole pieces of a magnet in 0.1 s. The magnetic flux between the pole pieces is 8 xx 10^(-4) Wb. Find the magnitude of induced e.m.f.

Why does a child feel more pain when she falls down on a hard cement floor, than when she falls on the soft muddy ground in the garden ?

Why does a child feel more pain when she falls down on a hard cement floor, than when she falls on the soft muddy ground in the garden ?