Answer:
The wavelength of the wave is 20 m.
Explanation:
Given that,
Amplitude = 10 cm
Radial frequency 
Bulk modulus = 40 MPa
Density = 1000 kg/m³
We need to calculate the velocity of the wave in the medium
Using formula of velocity

Put the value into the formula


We need to calculate the wavelength
Using formula of wavelength


Put the value into the formula


Hence, The wavelength of the wave is 20 m.
Mass is the physical quantity
Answer:
Star A is closer than Star B
Explanation:
As we know that in parallax method of distance measurement the angle subtended by the star when it covers a distance of one Parsec arc length, it is known as parallax angle
Here we can say

so we have

so here we have
angle subtended by Star A = 1 arc sec
angle subtended by star B = 0.75 arc sec
now we have
distance for star A is given as

distance of star B is given as

So star A is closer than star B