Replace the question mark with the correct number in the below-given picture?

What demands an answer, but asks no questions

What happened when the wheel was invented?

A quarter is one-fourth of a dollar but Mr. John has changed the equation as below :

DOLLAR * 4 = QUARTER

Can you replace each letter with a digit to make the above solution correct?

Solve the rebus riddle in the picture below.

Find The Next Number in the series:

12 13 15 17 111 113 117 119 123 ?

A King wants to send the diamond ring to his girlfriend securely. He got multiple locks and their corresponding keys. His girlfriend does not have any keys to these locks and if he sends the key without a lock, the key can be copied in the way. How can King send the ring to his girlfriend securely?

You need to arrange three 7 and mathematical symbols to form number 1?

There was a blind beggar living on the footpath of a street. Suddenly one day, the beggar's brother died. What was the relation of the blind beggar with the person who died?

PS: Brother is not the answer.

This puzzle is for Harry Potter fans. Do you know why Tom Riddle is called Lord Voldemort?