the relation that relates the speed of wave, frequency of wave and wavelength is given as
wavelength = 
the speed of wave in a medium remains constant. hence the wavelength is inversely related to the frequency of wave.
that means, as the frequency is increased, the wavelength decreases and vice versa.
hence the correct choice is
B decreases
Answer:
The speed of meteoroid is 21.61 km/s in south-east.
Explanation:
Given that,
A meteoroid is traveling through the atmosphere at 18.3 km/s. while descending at a rate of 11.5 km/s it means 11.5 km/s in south.
We need to draw a diagram
Using Pythagorean theorem




Hence, The speed of meteoroid is 21.61 km/s in south-east.
(1)
Cheetah speed: 
Its position at time t is given by
(1)
Gazelle speed: 
the gazelle starts S0=96.8 m ahead, therefore its position at time t is given by
(2)
The cheetah reaches the gazelle when
. Therefore, equalizing (1) and (2) and solving for t, we find the time the cheetah needs to catch the gazelle:



(2) To solve the problem, we have to calculate the distance that the two animals can cover in t=7.5 s.
Cheetah: 
Gazelle: 
So, the gazelle should be ahead of the cheetah of at least

Copper, gold and silver are three of them.