What has one letter and starts with an E?

Riddle me this, Riddle me that,
What am I? I am made of wood, but you can't see me down?

In an interview, a boy was asked an unusual question 'How two persons sitting with a table in between them can't see each other?' He was unable to reply. Can you?

You throw me out when you want to use me and you take me in when you don't want to use me.

Who Am I?

Always in you, Sometimes on you;

If I surround you, I can kill you.

What am I?

John enters a small room. The Door Closes.
When the door opens, John is in a larger room.

Explain?

My first is in chocolate but not in ham. My second is in cake and also in jam. My third at tea time is easily found. Altogether, this is a friend who is often around. What is it?

You Throw The Outside, Cook The Inside
Eat The Outside, Throw The Inside.

What Is It?

There are a number of books on a shelf. If one book is the 4th from the left and 6th from the right, how many books are on the shelf?

I get hot but I never sweat,
I cook food but I am not a chef,
I have a door but you can't enter me,
I have a light but I am not a lamp.
Who am I?