What does this simple rebus mean?

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

What is always in front of you but can’t be seen?

I have a five and a three-gallon jar. Assuming there is an infinite supply of water, how can I measure one-gallon water?

John killed hundreds of people mercilessly and yet the police were not able to put her behind the bars. Why?

If you're 8 feet away from a door and with each move you advance half the distance to the door. How many moves will it take to reach the door?

The teacher told the student that if he told a lie then he will be expelled from school and if he told the truth then he still is expelled from school.

What can a student say to prevent his being expelled from school?

There are three light switches outside a room. One of the switches is connected to a light bulb inside the room.
Each of the three switches can be either 'ON' or 'OFF'.

You are allowed to set each switch the way you want it and then enter the room(note: you can enter the room only once)

Your task is to then determine which switch controls the bulb?

Rahul decided to meet Simran so he boards a local train from Bombay station. Just after the station, there is a 1km long tunnel. The train starts and is now accelerating. Rahul is a claustrophobic guy, so what is the best position for him to sit?

Can you make numbers like 24, using numbers 3,3,7 & 7 with any arithmetic operator?