1) "Love" is stronger. I like yogurt, but I love ice cream.
2) "Love" can just be a strong form of like.
However, "love" can include erotic (sexual) feelings. "Like" usually does not.
"I like Jeff a lot" suggests that Jeff and I are friends.
"I love Amy" is ambiguous. You have to guess from context. It might mean that we are just friends, or it might mean that we are a couple. If a pair of people are described as "lovers," a sexual relationship is implied.