Answer:
Light refracts when its speed changes as it enters a new medium.
Explanation:
Bending of light wave while it entering a medium with different speed is called refraction of light. Light passing from a faster medium to the slower medium bends the light rays toward the normal to boundary between two media. The amount of the bending of light depends on refractive index of the two media which is described by the Snell's Law. The angle of incidence is not equal to angle of refraction. Rainbow is caused but this refraction phenomena. Also Refraction is used in magnifying glasses, prism and lenses
Answer:
Standard deviation = 3
Explanation:
Given


Required
Determine the standard deviation
First, we need to determine the variance;

This gives:



Know that:

Where SD represents standard deviation
This gives

Take square root


Answer:
The difference is 7.6 grams.
Explanation:
In mathematics the difference of two numbers is express as the subtraction between them:

So to find out the difference between the two measured masses, a will be represented by 123.6 grams since is the bigger number, and b by 115.972 grams.
Therefore, it is get:

<u>Hence, the difference is 7.6 grams. </u>
The result of 7.628 will be expressed as 7.6 to have the correct number of significant figures.
Notice how that can be express in units of kilograms too since there is 1000 gram in 1 kilogram:
⇒ 
Answer:

Explanation:
Given that
The speed of the airplane ,v= 142 m/s
The speed of the air ,u = 30 m/s
Lets take angle make by airplane from east direction towards north direction is θ .
Now by using diagram ,we can say that

Now by putting the values in the above equation we get



Therefore the angle will be 12.19° .
Answer:
h = 1.02 m
Explanation:
This is a fluid mechanics exercise, where the pressure is given by
P =
+ ρ g h
The gauge pressure is
P -
= ρ g h
In this case the upper part of the tube we have the atmospheric pressure. and the diver can exert a pressure 10 KPa below the outside pressure, this must be the gauge pressure
= P - 
= ρ g h
h =
/ ρ g
calculate
h = 10 103 / (1000 9.8)
h = 1.02 m
This is the depth at which man can breathe