Answer and Explanation:
In optics, a CoC(Circle of Confusion) is defined the minimum cross section of a paraxial bundle of rays made by a lens which is sphero-cylindrical type and can be viewed as an optical spot, which do not converge perfectly at the focus while a point source is being imaged due to spherical aberration.
The Circle of Confusion is also referred to as circle of indistinctness or a blur spot
Answer:
Scalar quantities have a size or magnitude only and need no other information to specify them. Thus, 10 cm, 50 sec, 7 litres and 3 kg are all examples of scalar quantities.
Explanation:
KE = (1/2) (mass) (speed)²
KE = (1/2) (20 kg) (40 m/s)²
KE = (1/2) (20 kg) (1,600 m²/s²)
KE = (10 kg) (1,600 m²/s²)
KE = 16,000 Joules
Answer:
The actual elevation angle is 12.87 degrees
Explanation:
In the attachment you can clearly see the situation. The angle of elevation as seen for the scuba diver is shown in magenta, we conclude that 
.
Using Snell's Law we can write:
,
Let's approximate the index of refraction of the air (medium 1 in the picture) to 1.
We thus have:
![\implies\theta_1=\arcsin[n_2\sin(\theta_2)]=\arcsin[1.333\sin(47)]\approx 77.13](https://tex.z-dn.net/?f=%5Cimplies%5Ctheta_1%3D%5Carcsin%5Bn_2%5Csin%28%5Ctheta_2%29%5D%3D%5Carcsin%5B1.333%5Csin%2847%29%5D%5Capprox%2077.13)
. Calling 
the actual angle of elevation, we get from the picture that 
