Please let me know about the material structure and properties of Solar energy devices.

Two stationary positive point charges, charge 1 of magnitude 3.45nC and charge 2 of magnitude 1.80nC , are separated by a distance of 40.0cm . An electron is released from rest at the point midway between the two charges, and it moves along the line connecting the two charges. What is the speed

5. Prove the Snell’s Law using:
   1. The fact that an homogeneous surface does not change the transversal momentum of the wave (Photon).
   2. Maxwell’s equations.
   3. The variational principle or Fermat’s principle.

Point charges of 9.00 nC are situated at each of three corners of a square whose side is 0.450 m .

a. What is the magnitude of the resultant force on a point charge of -4.00 μC if it is placed at the center of the square?

b. What is the magnitude of the resultant force on a point charge of -4.00 μC if it is placed at the vacant corner of the square?

Discuss the basic aspects of Tight-binding approximation (what is it, how and when this model is applicable, it's motivation, why is it important, it's limitations)? What are the differences and similarities of tight-binding model and free-electron model?

The speed of a projectile when it reaches its maximum height is 0.56 times its speed when it is at half its maximum height. What is the initial projection angle of the projectile?

A communications satellite is in a synchronous orbit that is 3.47

Two cars collide at an intersection. Car A, with a mass of 2000 kg , is going from west to east, while car B, of mass 1400 kg , is going from north to south at 14.0 m/s . As a result of this collision, the two cars become enmeshed and move as one afterwards. In your role as an expert witness, you inspect the scene and determine that, after the collision, the enmeshed cars moved at an angle of 60.0 ∘ south of east from the point of impact. How fast were the enmeshed cars moving just after the collision? How fast was car A going just before the collision?

An 7.5 g ice cube at −10°C is put into a Thermos flask containing 150 cm³ of water at 21°C. By how much has the entropy of the cube–water system changed when equilibrium is reached? The specific heat of ice is 2220 J/kg · K. (The latent heat of fusion for

water is 333 kJ/kg.)

A demonstration gyroscope wheel is constructed by removing the tire from a bicycle wheel 0.655 m in diameter, wrapping lead wire around the rim, and taping it in place. The shaft projects 0.190 m at each side of the wheel, and a woman holds the ends of the shaft in her hands. The mass of the system is 9.50 kg ; its entire mass may be assumed to be located at its rim. The shaft is horizontal, and the wheel is spinning about the shaft at 4.90 rev/s .

a) Find the force each hand exerts on the shaft when the shaft is at rest.

b) Find the force each hand exerts on the shaft when the shaft is rotating in a horizontal plane about its center at 4.80×10^?2 rev/s .

c) Find the force each hand exerts on the shaft when the shaft is rotating in a horizontal plane about its center at 0.320 rev/s .

d) At what rate must the shaft rotate in order that it may be supported at one end only?

(a) The radioisotope 40K constitutes 0.0117% of naturally occurring potassium and has a half life of 1.28´109 years. Calculate the activity of a 1.00 kg sample of potassium chloride (KCl). You may assume that 40K is the only radioisotope present in the sample. A mole of potassium chloride has a mass of 74.55 g

Hint: You will need to calculate the number of 40K atoms in the sample.Type or paste question here

(b) The plutonium batteries in Voyager 1 had a power output of 470 W when the spacecraft was launched in 1977. After how many years following launch will the power output have dropped to 300 W?

As a red giant, the Sun’s luminosity will be about 2000 times greater than it is now. Calculate the surface temperature of the Earth under these conditions assuming that the Earth is still at 1 AU and that the photosphere of the sun is well within 1 AU.

the answer should be about 1900 K but im not sure what am i getting wrong in my calculations, please help!

The

cat righting reflex

is a cat's innate ability to orient itself as it falls in order to land on its feet. The

righting reflex begins to appear at 3

–4 weeks of age, and is perfected at 7 weeks. The minimum height

required for this to occur in most cats would be around 30 cm.

You are part of an engineering team trying to reproduce this in a mechanical cat. Your prototype, aptly

named Katt, when dropped motionless, upside down from 2.5 m, can right itself before it hits the ground

by rotating its “tail”. Katt’s body is a solid cy

linder 30 cm in length and 15 cm in diameter, with a mass of

3.0 kg. Attached to the center of one end of the body is Katt's tail, a 20

-cm long rod which extends out

perpendicular to Katt's body and has only 10% the mass of the body. The tail will rotate due to a s

mall

electric motor in the body that produces a constant torque. In order to order the piece, determine the

angular speeds it will need to deal with.

A bullet of mass m = 29 g is fired into a wooden block of mass M = 4.9 kg as shown in the figure below. The block is attached to a string of length 1.5 m. The bullet is embedded in the block, causing the block to then swing as shown in the figure. If the block reaches a maximum height of h = 0.27 m, what was the initial speed of the bullet?