Can you replace the question mark with the correct number?

What is the difference between a jeweller and a jailer?

I never stop running even when I standstill. If I am formed by joining two identical bodies together, can you guess who I am?

A man looks at a painting in a museum and says, “Brothers and sisters I have none, but that man’s father is my father’s son.” Who is in the painting?

On a bright sunny day, two fathers took their son fishing in the lake. Each man and son were able to catch one fish. When they returned to their camp, there were only three fishes in the basket. What happened?

PS: None of the fish were eaten, lost, or thrown back.

How many points are there on the globe where, by walking one mile south, then one mile east and then one mile north, you would reach the place where you started?

When it's bad luck to meet a black cat?

If,

A = 1

B = 2

C = 3

...

...

Z = 26.

Based on above rule, you need to find an eleven letter word whose letter sum is equal to 52.

Spot 5 differences in two Christmas tree below:

I have a mouth but I don't eat.
I have a bank but have no money.
I have a bed but i dont sleep.
I wave but have no hands.

Who Am I ?