You Do Need power plug adapter while traveling from Uruguay to Brazil.

Here is Why You Need An Adapter

The outlet and plug type used in Brazil are C and N and in Uruguay are C, F and L. This is how they look like.

Uruguay

In Uruguay, outlets of type C, F and L are in use.

Type C

Type F

Type L

Brazil

In Brazil, outlets of type C and N are in use.

Type C

Type N