Answer:
Regions near rivers have water surfaces that rapidly change in temperature from cold to hot.
you have your own answer i only selected which is suitable for me . none of them is wrong they re excellent
Here, you need to use your "Protractor" as it is given in the question, but we can calculate the value with the help of our mathematical calculation too:
[ Protractor can be use only in real life, not here ]
Draw an imaginary line from initial position to final position.
Now, In that triangle, tan x = P/B
tan x = 1.4 / 2
tan x = 0.70
x = tan⁻¹ (0.70)
x = 35 [ tan 35 = 0.70 ]
In short, Your Answer would be 35 degrees
Hope this helps!
The beat frequency is the concept required to develop this process. The phenomenon is generated when you have two waves but their frequencies do not differ greatly. So the beat frequency will be the difference between those two waves. For this case we have the difference and one of the waves, therefore,

Our values are given as,


Using the formula of the frequency I will have,

Replacing we have,



The possible values are two: 1045Hz and 1055Hz