suppose the mass of a metal object be m and its specific heat capacity be s, and, H joules of heat is required to raise its temperature by t degrees Celsius
Than H is given by relation,

Now if this object is cut in two half's, than mass of half part will also be half i.e. M/2
So heat required to heat the half part will be
Hence, the heat required to raise the half object to a specific temperature will also become half.