Choose the correct statements from the following list referring to white dwarfs. (Give ALL correct answers, i.e., B, AC, BCD...)

A) White dwarfs are less dense than red giants.

B) White dwarfs cool slowly because they are small and eventually fade-out to become black dwarfs.

C) The pressure that balances gravity in a white dwarf is called degenerate electron pressure.

D) Stars with a mass like the Sun will end up as a white dwarf star.

E) White dwarfs with mass greater than 1.4 times the Sun's mass cannot exist.

F) The power source of white dwarfs is left-over heat. G) White dwarfs are the coolest main sequence stars.

A gigantic parallel plate capacitor with area of plates of 1.1x108 m 2 and separated by distance 1500 m connected to source of a potential difference 35 million volts. Define potential energy of the capacitor.

what will be transient telegrapher's equation solution using laplace transforms if R,G parameter is not zero.

Where R= RESISTOR OF WIRE AND G= conductance between line.

A converging lens forms an image 20 centimeters  high of an object that is 5 centimeters high.

part a calculate the magnification factor m of the lens

part b Explain how you can calculate the distance from the object if you know the lens has a focal length of  f centimeters.

part c If the lens has a focal length of 10 centimeters calculate the distance to the image if the object is placed at a distance of 25 centimeters from the lens.

part d Indicate if the image formed in part c is  real or virtual and if it is upright or inverted.

The mass of Uranus is 8.68 x 10²⁵ kg. That’s 14.536 times more than the mass of Earth.

What is the difference between the forces due to Uranus on a 1.0 kg mass located at the near side of Titania and at the far side of Titania? Titania has a mean radius of 789 km and a mean orbital radius about Uranus of 436,300 km. (Enter the magnitude in newtons.)

Compare this difference to the difference for Earth due to the Moon, 0.22 ✕ 10⁻⁵ N. (Tidal forces are the cause of volcanic activity on some moons.)

Calculate the mass (in kg) of the Sun based on data for Uranus's orbit. (Use G = 6.67 ✕ 10⁻¹¹ N · m²/kg² in your calculations. Round your answer to at least four significant figures.)

Compare the above calculated value with the Sun's actual mass. (Round your answer to at least three decimal places.)

A car drives around a curve with radius 420 m at a speed of 37 m/s. The road is banked at 5.4°. The mass of the car is 1500 kg. (a) What is the frictional force on the car? (b) At what speed could you drive around this curve so that the force of friction is zero?

The heavy boy and light girl are balanced on the seesaw. If they both move inward so that each is exactly half the original distance from the pivot, then the 1) boy's end will move downward. 2) girl's end will move downward. 3) seesaw will remain in balance. If the fulcrum of the seesaw is repositioned so each can sit at an END of the board and be in balance, then if each moves inward half way the 4) boy's end will move downward. 5) girl's end will move downward. 6) seesaw will remain balanced. choose one answer from (1-3) and one answer from (4-6)

Briefly explain the main differences of heat capacity approaches of solid between Einstein, Debye and classic thermodynamic model.

Suppose that a person has an average heart rate of 98.0 beats/min. (Express your answers to problems in this section to the correct number of significant figures and proper units.)

(a)How many beats does he or she have in 3.0 y?

(b) How many beats does he or she have in 3.00 y?

(c) How many beats does he or she have in 3.000 y?

†

Can someone explain what internal energy is and how to calculate it when given mass, friction, speed etc? Is it always the same thing as non-conservative work..?

A baseball is thrown from the roof of 23.5 m -tall building with an initial velocity of magnitude 10.5 m/s and directed at an angle of 52.4° above the horizontal.

What is the speed of the ball just before it strikes the ground? Use energy methods and ignore air resistance.

What is the answer if the initial velocity is at an angle of 52.4° below the horizontal?

If the effects of air resistance are included, will part (a) or (b) give the higher speed? Why?

Bohr theory of the atom:

In the hydrogenic Bohr orbit of quantum number n compute the ratio of the circumference of the orbit to the wavelength of the electron. Provide an interpretation of this result in terms of the concepts of de Broglie.

Treating the Bohr orbit as a circulating electrical current, compute the magnetic moment of the electron in a Bohr orbit of quantum number n (Hint: use Ampere’s law). What is the ratio between the magnetic moment and the angular momentum?

1-The Large Hadron Collider in Europe smashes together near-light speed protons to discover new fundamental particles of nature. As part of the detection process, the “debris” from the collision is made to pass through a magnetic field. What is the purpose of this magnetic field?

2-If you are outside on a dark night you might see an aurora (i.e. northern or southern lights). What produces this display and why is it most common at middle to high latitudes?

A horizontal disk with radius R and charge density σ is centered originally. A particle with charge Q and mass m is in equilibrium at a height h above the center of the plate, as shown. A gravitational field is present. R = 1.5 m σ = -5⋅10-7 C / m2 h = 2 m Q = -2 µC a) Calculate the mass m of the particle if it is at equilibrium (use g = 9.81 m / s2 ). b) Calculate the electric potentials created by the disc at the following two positions on the Y axis: at y = 2 m and at y = 4 m. c) If we remove the gravitational field, calculate how fast the particle will reach the position y = 4 m. d) In the absence of a gravitational field, calculate the external work required to bring the particle Q from infinity to the center of the disc (i.e. y = 0 m), without variation of speed. (Reminder: V∞ = 0)

Answer the following four sub-questions. Each sub-question is independent and has no no link with the other sub questions. a) Two neutral spheres are spaced 3 m apart. Calculate how many electrons must be transferred from one sphere to another so that they each experience a force of 14 N, and say whether the forces will be attractive or repulsive. b) Calculate the uniform electric field to be applied parallel to a moving proton at 2⋅106 m / s in order to immobilize it in 20 µs, and say if this field must be oriented in the direction of speed or in opposite direction. c) A long insulating cylinder has a charge density of -1 µC / m3 . The material component the cylinder suddenly becomes conductive; we see that the density load area is then -1 µC / m2 . Calculate the radius of the cylinder. d) Calculate the magnitude of the electric field at position r = 10 cm in question 4. Your gait must show, among other things, that the load (or surface density) of the shell thin has no effect on your response.