Compound; consists of atoms of two or more different elements bound together,can be broken down into a simpler type of matter (elements) by chemical means (but not by physical means) has properties that are different from its component elements, and always contains the same ratio of its component atoms.Mixtures; Note that a mixture:consists of two or more different elements and/or compounds physically intermingled, can be separated into its components by physical means, and often retains many of the properties of its components.
Altered means to change something.
Answer:
Explanation:
It is a case of oscillation by simple pendulum . Expression for simple pendulum is given as follows
T = 
where T is time period , l is length of pendulum and g is acceleration due to gravity .
, f is frequency of oscillation
For the given case

subsequently length becomes half so

dividing

f = 
frequency of oscillation becomes √2 times.