Questions

The size of gear is usually specified by pitch circle diameter.

Molecular compounds are those with covalent bonds between the elements and those elements are typically non metals.

Here in the given options, Ar is an element. NaI has an ionic bond. Hence, N2O4 has a covalent bond between the two non metals and is a molecular compound.

Orissa

Here in this declaration public static void main string[] args, each keyword has its importance.

1. public - Here public is an access specifier which allows the main method to be accessible everywhere.

2. static - static helps the main method to get loaded without getting called by any instance/object.

3. void - void clarifies that the main method will not return any value.

4. main - It's the name of the method.

5. String[] args - Here we are defining a String array to pass arguments at the command line. args is the variable name of the String array.