Which one of the following statements is INCORRECT regarding Van de Graff generator?

Which one of the following statements is INCORRECT regarding Van de Graff generator? Correct Answer Cannot be constructed inside a building

CONCEPT:

• A Van De Graff generator is used to accelerate charged particles.

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• This is achieved by means of a moving belt and suitable brushes, through which charge is continuously transferred to the shell and this, in turn, produces a potential difference of the order of several million volts.
• This large potential difference thus created, is used to accelerate charged particles to very high speeds.
• The electrostatic generator that uses a moving belt to accumulate electric charge on a hollow metal surface on the top of an insulated column which creates a very high electric potential/Voltage is called the Van de Graff generator. 

EXPLANATION:

• The potential produced by the Van de Graaff generator can be used to accelerate the particles and by using these accelerated particles structure of matter can be studied 
• The van de Graaff generator can produce millions of volts.
• The Vand de graff generator can be constructed inside buildings. Therefore option 4 is wrong.
• Hence, option 4 is the answer