Hich subatomic particle has a neutral charge? a) electron b) neutron c) nucleus eliminate d) proton

The subatomic particle with a neutral charge is the NEUTRON.

Unlike the proton which has a positive charge, and the electron that has a negative charge, the NEUtron has a NEUtral (no) charge.

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

there are two significant figures.