Answer:
a. 8p
Explanation:
We are given that
Radius of hollow sphere , R1=R
Density of hollow sphere=
After compress
Radius of hollow sphere, R2=R/2
We have to find density of the compressed sphere.
We know that
Therefore,
Volume of sphere=
Using the formula
Hence, the density of the compressed sphere=
Option a is correct.
Answer: Yes
Air serves as a propagation medium.
Explanation:
Propagation of sound wave require a medium for transmission. Sound is produced by vibrating objects, The matter or substance through which sound is transmitted is called a medium. It can be solid, liquid or gas. Therefore to propagate sounds (human voice) from one end of a lecture hall to the other we need a propagation medium which is air. Air serves as a propagation medium.
Answer: The five general characteristics of the nearest stars are the brightness, color, surface temperature, size, and mass.
Explanation:
The mass of a star can be described as being measured with our sun at 1 solar mass. One star can equal the size of our sun. There is one star named, Rigel, that is bigger than the Earths sun. Each star will vary in its density.
The size of the star, as stated above, can be the size of our sun and sometimes larger. The size is measured by solar radii.
Stars vary in their temp. They range anywhere from -273.15 degrees Celsius to 50,000 K. The temp is based on the Kelvin scale.
The stars brightness are always based on luminosity and magnitude.
The stars colors will vary and is based on the temperature of the surface of the star. Some stars are red in color, white in color, and some even have a bluish color.
The special feature of the upper mantle is the asthenosphere.It is located just below the lithosphere and is made up of rocks that is fluid and can move.The fluidity of these rocks powered the movement of the tectonic plates on the earths crust.Circular convection cycles in the hot,fluid upper mantle rock move the plates over the surface of the earth.