A voltage transformer transforms the frequecy of the power grid ? True or false ? Explain

False. Because Transformer transform same frequency  as power gird supplied

False.

By the name voltage transformer transforms the level of voltages. i.e it transforms the electric potential from one level another level. that's it is being called PT. 

Transformer working with AC power supply would only change the voltage and the frequency is constant as supplied by the power grid.

False !

Basically, a voltage transformer changes electrical energy of a given voltage into electrical energy at a different voltage level ( Up or Down).

false: because the transformer change the voltage without changing frequncy  

I suppose a transformer working with AC power supply would only change the voltage, and the frequency is constant as supplied by the power grid.

The only device I know that can change power frequency at distribution side is variable speed drive (VSD) by converting from AC to DC and back to AC.

true, because whatever frequency goes into the primary comes out the secondary

false,transformer can't change frequency

False, transformer just control output voltage up or down up to turns ratio

yes