The Huygens<span>-Fresnel </span>principle<span> states that every point on a wavefront is a source of wavelets. These wavelets spread out in the forward direction, at the same speed as the source wave. The new wavefront is a line tangent to all of the wavelets. </span>
Answer:
(a) Surface charge density is the charge per unit area.

(b) 
(c) 
Explanation:
(a) Surface charge density is the charge per unit area. The area of the square plate can be calculated by its side length.

Half of the total charge is distributed on one side and the other is distributed on the other side.
Therefore, surface charge density on each face of the plate is

(b) To find the electric field just above the plate, Gauss' Law can be used. Normally, Gauss' Law can only be used in infinite sheet (considering the flat surfaces), but just above the surface can be considered that the distance from the surface is much much smaller than the length of the plate (x << l).
In order to apply Gauss' Law, we have to draw an imaginary cylinder with radius r. The cylinder has to stay perpendicular to the plane.

The direction of the electric field is in the upwards direction.
(c) The magnitude of the electric field is the same as that of upper side. Only the direction is reversed, downward direction.
Answer:
I think the answer is 18 km/h
Explanation:
Answer: The mean of the samples is 32.325.
Proportion of the defective unit is =
Explanation:
The point estimate of the mean of the sample:
First calculate the mean of the 40 samples:


The mean of the samples is 32.325.
Defected pieces in the samples whose life span is less than the 26 days = 2
Proportion of the defective unit is =
Answer:
3, it's the igneous rock, sedimentary rock, and metamorphic rock i believe
Explanation: