Calculate the Kovats retention index for an unknown using the retention times 1.4 min1.4 min for CH4,CH4, 12.2 min12.2 min for octane, 15.9 min15.9 min for the unknown, and 17.5 min17.5 min for nonane.

c. because step up transformer steps up the input voltage i.e increases the input voltage  

the number of turns are greater on the secondary side of step up transformer  

transformer does not handle dc current

the transfer of heat by electromagnetic radiation is called thermal radiation . it is usually carried out by electromagnetic waves in an energy range just below the visible spectrum, which is the infrared range.

so the answer would be radiation.

: )