You may enter, but you may not come in. I have space, but no room. I have keys, but open no lock. What am I?

I start and end with 500 and carry a 5 in my heart. But I require the first letter and the first number to be complete. I am the name of a King.

Who am I ?

The following sentence is false. The preceding sentence is true.
Are these two sentences true or false?

I have a hole in my back and legs I lack.
I live where I can’t breathe and I eat without teeth.
What am I?

One of the leprechaun is missing if you see the two pictures attached to this question. Where did he go? When he comes back, do you know where has he been?

Open a Laptop which is password protected. Hint for the password is given as below:

1 mobile 3 books 2 Boards 1 night 4 balls 2 lighters 1 ghost 1 hat 3 watches

Find the number of squares in the below-given picture.

There was a man he lives in a hotel each morning he presses the first floor button each evening if there is a person in the elevator he asks him to press the 10 floor button if there is no one in the elevator he takes the stairs why.

If you had a pizza with crust thickness 'a' and radius 'z', what's the volume of the pizza?

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

Explain?