Answer:
Volume of given mass of gas is inversely proportional to pressure of gas
Explanation:
Boyle's law: It states that the volume of given mass of gas is inversely proportional to the pressure of gas at constant temperature.
Mathematical representation:
Suppose, a gas of mass m
T=Constant temperature
V=Volume of gas
P=Pressure of gas
Then, 
Theories have both an explanatory an a predictive function. True
Answer:
B. Two waves have displaced in opposite directions
Explanation:
Interference occurs when two waves meet at a point in space. When this occurs, two extreme conditions can occur:
- if the two waves are in phase (=displacement in the same direction), the amplitude of the resultant wave is equal to the sum of the amplitudes of the two waves:
A = A1 + A2
and this condition is called constructive interference
- if the two waves are in anti-phase (=displacement in opposite directions), the amplitude of the resultant wave is equal to the difference of the amplitudes of the two waves:
A = |A1 - A2|
and this condition is called destructive interference. Note that if A1=A2, the amplitude of the resultant wave is zero.