The most commonly used retarder in cement is

Cast iron contains carbon approximately

The most important constituent of an oil paint, is

Pick up the correct statement from the following:

The proportions of charcoal, saltpetre and sulphur in gun powder by weight, are respectively:

Manganese steels

The size of mould for bricks, is generally kept

The type of roof which slopes in two directions with a break in the slope on each side is known as

A good building stone should not absorb water more than