Concept explainers
(a)
The fraction of the galaxy’s volume is occupied by stars.
(a)
Answer to Problem 34PQ
The fraction of the galaxy’s volume is occupied by stars is
Explanation of Solution
Write the equation of fraction of galaxy’s volume is occupied by stars.
Here,
Write the expression for the volume of star.
Here,
Rewrite the expression for the fraction.
Conclusion:
Substitute
Thus, the fraction of the galaxy’s volume is occupied by stars is
(b)
The mean free path of a star through galaxy.
(b)
Answer to Problem 34PQ
The mean free path of a star through galaxy is
Explanation of Solution
Write the equation of mean free path.
Here,
Conclusion:
Substitute,
Thus, the mean free path of a star through galaxy is
(c)
The probability of collision.
(c)
Answer to Problem 34PQ
The probability of collision is
Explanation of Solution
Write the equation for the probability.
Here,
Conclusion:
Substitute
Therefore, the probability of collision is
Want to see more full solutions like this?
Chapter 20 Solutions
Physics for Scientists and Engineers: Foundations and Connections
- In the deep space between galaxies, the number density of atoms is as low as 106 atoms/m3 and the temperature is a frigid 2.7 K. a) What is the pressure, in pascals, in the region between galaxies b) What volume, in cubic meters, is occupied by 2.5 mol of gas? c) If this volume is a cube, what is the length of one of its edges, in kilometers?arrow_forwardOne cubic centimeter of a typical cumulus cloud contains 310 water drops, which have a typical radius of 10-5m. (a) How many cubic meters of water are in a cylindrical cumulus cloud of height 3.1 km and radius 1.1 km? (b) How many 1-liter pop bottles would that water fill? (c) Water has a density of 1000 kg/m3, How much mass does the water in the cloud have?arrow_forwardIron has a density of 7.87 g/cm3, and the mass of an iron atom is 9.27 * 10-26 kg. If the atoms are spherical and tightly packed, (a) what is the volume of an iron atom and (b) what is the distance between the centers of adjacent atoms?arrow_forward
- if there are 1 million electronic components on a semiconductor chip that measures 5.0 mm by 5.0 mm: (a) how much area does each component occupy? (B) if the individual components are square, how long is each on a side?arrow_forwardImagine a very huge industrial metallic bucket is in the shape of the frustum of a right circular cone whose top and bottom diameters are 10 m and 4 m respectively and a height of 4 m. a) what is the curved surface area of the bucket? b) what is the volume of water if it’s to be filled to the brim if the thickness of the metal is 0.60 meters including the base?arrow_forwardA light-year is the distance light travels in one year (at speed 2.998 x 10^8 m/s). (a) How many meters are there in 1.00 light-year? (b) An astronomical unit (AU) is the average distance from the Sun to Earth, 1.50 X 10^8 km. How many AU are there in 1.00 light-year?arrow_forward
- A) A typical dust grain has a radius of about 0.1 micrometers and a mass of 10-14 grams. Roughly how many dust particles are in a cloud containing 1000 Msun of dusty gas if 1% of the cloud's mass is in the form of dust grains? B) What surface area would be covered by these grains if you put them side by side? Assume these grains are spherical. Answer in square light-years. C) Estimate the total surface area covered by the cloud assuming it's matter density is like that of a typical molecular cloud, about 10-21 g/cm3 (Hint: first calculate the clouds volume from it's mass and density, then determine its radius using the formula for volume of a sphere) Answer in square light-years. D) Comparing all above answers, What are the chances (very roughly) that a photon passing through the cloud will hit a dust grain?arrow_forward(II) A typical atom has a diameter of about 1.0 x 10–10 m. (a) What is this in inches? (b) Approximately how many atoms are along a 1.0-cm line, assuming they just touch?arrow_forward(a) Show that the terms in Schrödinger’s equation have the same dimensions. (b) What is the common SI unit for each of these terms?arrow_forward
- Grains of fine California beach sand are approximately spheres with an average radius of 50 m and are made of silicon dioxide, which has a density of 2600 kg/m3.What mass of sand grains would have a total surface area (the total area of all the individual spheres) equal to the surface area of a cube 1.00 m on an edge?arrow_forwardFor (b), why do we divide the (100Wx8h) by (103Wh)? I get that we need to cancel out the Wh, but why do we divide by 103 specifically?arrow_forwardIn the body-centered cubic phase of plutonium, the volume of the unit cell is 4.910 x 10–23 cm3. If the atoms along a diagonal of the unit cell are touching, what is the atomic radius, in cm, of a plutonium atom?arrow_forward
- Physics for Scientists and Engineers: Foundations...PhysicsISBN:9781133939146Author:Katz, Debora M.Publisher:Cengage Learning