Globular clusters were classified by Shapley and Sawyer as being on a scale from 1 to 12 where 1 is very loosely packed central area and 12 is highly packed central area. As a visual astronomer, it seems difficult to judge the concentration of a globular cluster.

Has anyone tried to classify globular clusters concentration classes for something like the Astronomical League Club for Globular Clusters? http://www.astroleague.org/al/obsclubs/globular/globular1.html

It seems that to judge concentration you first need to know what percentage of the diameter of the globular cluster corresponds to the packed core. Visually, knowing the official stated size seems to be required since without that, it is hard to say how concentrated the core is as a glow percentage.

Can any human eye get anywhere near detecting all twelve steps of concentration? It is easy enough to distinguish 3 or 4 levels, but twelve seems daunting.

How can I attempt to properly judge globular clusters on the Shapley and Sawyer scale?

A solenoid runs through the x-y plane with n = 1,185/m. A circular wire wrapped 18 times with a radius of 0.49 meters is placed in the x-y plane in the solenoid. The solenoid's current increases from 6 amps to 28 amps running clockwise in a time of 2.4 millis-seconds. If the resistance of the circular wire is 2.4 Ohms, what is the amount, in amps, and direction of the average induced current in the circular wire? Indicate clockwise by including a negative sign, but do not include a sign for counter-clockwise.

You have 11m of 0.60mm diameter copper wire and a power supply capable of passing 25Athrough the wire.

Part A

What magnetic field strength would you obtain inside a 2.0-cm-diameter solenoid with the wire spaced as closely as possible?

Part B

What magnetic field strength would you obtain at the center of a single circular loop made from the wire?

A projectile (mass = 0.25 kg) is fired at and embeds itself in a stationary target (mass = 2.54 kg). With what percentage of the projectile's incident kinetic energy does the target (with the projectile in it) fly off after being struck?

Starting with Maxwell's equations show that the magnetic field satisfies the same wave equation as the electric field. in particular, that is, too, propagates with the same speed.

A) What is the speed of the 0.350-kg puck after the collision?

Express your answer to three significant figures and include the appropriate units.

B) What is the speed of the 0.950-kg puck after the collision?

Express your answer to three significant figures and include the appropriate units.

1. As the earth rotates, what is the speed of a physics student in Miami, Florida, at latitude 26degrees Ignore the revolution of the earth around the sun. The radius of the earth is 6400 km.

2. What is the speed of a physics student in Fairbanks, Alaska, at latitude 65??

An electric charge on the x axis oscillates sinusoidally about the origin. A distant observer is located at a point on the +y axis.

Part A

In what direction will the electric field oscillate at the observer's location?

x,y or z?

Part B

In what direction will the magnetic field oscillate at the observer's location?

x,y or z?

Part C

In what direction will the electromagnetic wave propagate at the observer's location?

+x,-x,+y,-y,+z, or -z?

1.) The speed of an electron is measured to within an uncertainty of 2.0x104 m/s. In how large a region of space is the electron likely to be found?

2.)The star nearest to Earth is Proxima Centauri, located at a distance of about 4.2 light years. (a) If one could travel there at 99% of the speed of light (0.99c), what would be the apparent distance to the star? (b) If you traveled to Proxmia Centauri at this high velocity, stayed there for 2 years, and then returned (also at 0.99c), how much time would have passed on Earth?

3.) (a) What is the wavelength of light for the least energetic photon emitted in the Balmer series of the hydrogen atom spectrum lines? (b) What is the wavelength of the series limit?

4.) How many electron states are there in the following shells: (a) n = 4, (b) n = 1, (c) n = 3, (d) n = 2?

5.) A sample of a certain metal has a volume of 4.0E-3 m3. The metal has a density of 9.0 g/cm3 and a molar mass of 60 g/mol. The atoms are bivalent. How many conduction electrons (or valance electrons) are in the sample?

The wavelength of the four Balmer series lines for hydrogen are found to be 410.1, 434.3, 486.6, and 655.9 nm. What average percentage difference is found between these wavelength numbers and those predicted?

A speeding car is traveling along a straight road with a constant speed of 100 km/hour. It passes a police car. The officer starts 5.00 s after the speeder passes. The police car accelerates uniformly (i.e., at a constant acceleration) for 10.0 s, at the end of which its speed is 120 km/hour. After that, the police car moves with the constant speed of 120 km/hour till it reaches the speeding car.

How far ahead of the police car is the speeding car when the police car stops accelerating? How long after it stops accelerating does the police car reach the speeding car?

In the figure the four particles form a square of edge length a = 5.60 cm and have charges q₁ = 9.22 nC, q₂ = -21.8 nC, q₃ = 21.8 nC, and q₄ = -9.22 nC. What is the magnitude of the net electric field produced by the particles at the square's center?

How did Einstein’s photoelectric effect prove that light has a wave-particle duality?

Discuss three of the historical astronomers described in the text and lectures, together with their contributions to astronomy.