Mét nåi h¬i b»ng thÐp cã khèi l-îng lµ 900 kg. Nåi h¬i chøa 400 kg n-íc. Gi¶ sö hiÖu suÊt sö dông nhiÖt cña nåi h¬i lµ 70%. CÇn bao nhiªu calo nhiÖt ®Ó n©ng nhiÖt ®é cña
nåi h¬i tõ 100C lªn 1000C, biÕt nhiÖt dung cña thÐp lµ 0,11 kcal/kg vµ cña n-íc lµ 1 kcal/kg

the number of protons in the nucleus of a given element. has slight luster and conducts electricity at high temperatures like metal.but like a nonmetal,boron is brittle and does not conduct electricity well at low temperatures. in graphite, carbon is a soft,brittle solid.it is reflective,ductile,or malleable.

there is none because earth is stationary and flat.

answer is: nuclear fusion produces elements that are heavier than helium.

nuclei combine to form a heavier nucleus, releasing energy.  

for example, fusion of hydrogen atoms at the sun.  

this fusion nuclear reaction is in the inner core of the sun and hydrogen (atomic number 1) is conveted into helium (atomic number 2).  

the inner core is the central region of the sun and all solar energy is produced in the core by nuclear fusion.