You Do Need power plug adapter while traveling from Tanzania to Ethiopia.

Here is Why You Need An Adapter

The outlet and plug type used in Ethiopia are C, F and G and in Tanzania are D and G. This is how they look like.

Tanzania

In Tanzania, outlets of type D and G are in use.

Type D

Type G

Ethiopia

In Ethiopia, outlets of type C, F and G are in use.

Type C

Type F

Type G