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1. Prove that spec of root 2 contains infinitely many powers of 2.

Spec of root 2 is that set of elements floor(k * (root 2)) ; k >= 0 . I have no idea of how I can prove the statement in the question. Prove that spec of root 2 contains infinitely many powers of 2. I need ideas on how to proceed. Thank you
2. E-k diagram what is k?

In the E-k diagrams for a semiconductor material,what exactly is k? I have read that it is a propagation constant,a wave vector. But does movement in the semiconductor material represent corresponding changes in k? I mean to ask if changes in k represent the physical movement in the...
3. What inside the band gap?

I am reading about solid state electronics(semiconductors). I've read that when atoms of many many atoms are brought close each other,as in a solid, the energy levels of energy states of different atoms get split up into different closely lying energy states collectively forming a band...
4. Hall Effect

We have an experiment on Hall Effect,in which we place a semiconductor material in the middle of a 2 poles of a magnet exactly in the middle so that a distance of 1 cm exists between the poles. Questions: 1.Why is a semiconductor placed?Will it make any difference with a metal? 2.Why a 1 cm...
5. Magnetism to test for movement?

They say it is impossible to know whether you're moving at constant velocity or at rest unless you look outside. How about this:(no gravity please) I take two known charges and hold them at a distance one above the other. They repel.That is l I know. Someone else outside says,that the...
6. Job description in computers and electronics

Hi. I am now to choose what I must study for engineering. So,I wanted some help.Everyone says "you must take what you like and what you will enjoy doing and what will make your job enjoyable". But,I don't know what I'll learn in engineering and what job I'll have to do. (I have to pick among...
7. Plane mirrors (multiple)

Homework Statement How many images of a symmetrically placed object will be formed if 2 plane mirrors are fitted on ADJACENT walls of a room and another one on the top(roof)? (mirrors are big) 2. The attempt at a solution According to me,9. because,3 direct images of the object are...
8. Capacitor discharge

Homework Statement A fully charged capacitor is connected in a closed circuit with nothing else in the circuit. So the capacitor starts discharging.At a certain instant of time the charge on the capacitor is reducing at the rate of 5 micro coulomb per second(dq/dt =5 μC per s). What is the...
9. Question regarding onto function

Hi. I know what an onto function is. I found this statement on a problem: f(x) is a function from a set Z onto itself. Now does this mean that f(x) is an "onto" function or is the word used just like that(like an english word)? What if it was: f(x) is a function from a set Z into itself...
10. Root of square of something

Consider this function: (x^2)^0.5 My text book considers this to be |x| (modulus of x). Is it correct? x^2 gives a positive quantity.On taking square root of that,we'll get either -x or +x. So why modulus? Also, (x^0.5)^2 This is modulus isn't it? Thank You
11. Physics homework on springs

Please consider the following case: Spring connected at both ends by some masses.Everything is ideal. Find the extension of the spring. http://img101.imageshack.us/i/unledpi.jpg/ http://img101.imageshack.us/i/unledpi.jpg/ My big question is ....if the spring extends by a length say...
12. Linear speed rolling

Homework Statement A point on the rim of the wheel of radius R under pure rolling has absolute ground speed of (v root 2) or v*(2)^(1/2).the angular speed of rotation is ω. At what horizontal distance from the instantaneous axis of the rim is the particle located? Homework...
13. Question about law of reflection

When is the law "the image is formed back in the mirror at a distance equal to that of the object from the mirror applicable? Consider a plane mirror,with a glass slab on it. Let an object be placed in front of it outside the slab, in air. Now due to normal shift the mirror will see the...
14. Glass slab with mirror at back

Homework Statement Please see here: http://img198.imageshack.us/i/unledev.jpg/ object placed 8 cm before the slab(6 cm thick,silvered at other end). The final image is formed 10 cm behind the mirror.Find refractive index of slab. 2. The attempt at a solution n is refractive index...

http://img51.imageshack.us/i/unledbh.jpg/" [Broken] http://img51.imageshack.us/i/unledbh.jpg/ please see the above image. if I is the current from left to right in the circuit, then what equation shall I use? V(BA) = I*R1 +I*R2 or V(BA)= I*R1 +I*R2 - 5 (counting the emf battery...
16. Difference between delta H and q?

what is the difference between delta H and q? delta H = delta U + P(delta V) so, delta H = delta U -W delta U=q + W so, q=delta U - W So now is there a difference between the two at all? Why then 2 separate quantities? Thank You
17. Is delta H a state function?(Hess Law?)

is delta H a state function??(Hess Law?) Is delta H a state function? We know that delta H=delta U+W (at const P) so, we also know that W is path dependent function.So delta H being a sum of delta U and a path dependent function must not be a state function.(point 1) But there is this Hess...
18. Is delta H=0 for isothermal process?

1.>Consider a gas in a vessel with a piston on top.Let it expand to a greater volume. So, delta H=delta U+delta(PV) but delta U is 0 as it is isothermal. now,as the number of moles of gas remains constant,delta(PV) is nR(delta T) which is again 0. SO delta H is 0. Thats what my book says...
19. Difference between Electric flux density,electric field strength .

Difference between Electric flux density,electric field strength..... I want to know the difference between,electric flux density and electric field strength.Are they the same? And also,there is a magnetic field(measured in Tesla),magnetic flux(in Weber),magnetic flux density(Weber per...
20. Help with terrestrial magnetism

I have a bunch of conceptual questions on Earth's magnetism. The problem is I have not understood the elements there. I am not able to visualize the magnetic field ,horizontal component,declination,inclination. I don't know the directions of them too. My book hasn't given pictures of them...
21. How to determine dsp2 or sp3 structure?

Taking an example as: [CuCl4]2- (charge =-2) I finding it very confusing to decide whether the structure would be dsp2 or sp3? There will 9 electrons in d orbital of Cu2+ in this compound. In the presence of Cl- ligand will one electron get transferred to 4p orbital or will it stay in the...
22. Themodynamics problem

Expansion irreversibly and isothermally of an ideal has from a volume of 2dm3 to 10 dm3 against a const pressure of 1 atm at 27 C .Find entropy change of the system and also surroundings due to the process. Heres my attempt: delta S=energy absorbed/temp for the system, = energy...
23. Basicity order questions

Hey folks. The orders given are stated in my book.I'm here to ask why. basicity: p-methyl aniline>m-()>aniline>o-() p exerts hyperconjugation and +I,m only +I ,but ortho exerts hyperconjugation and higher +I. Shouldn't o-methyl aniline have high basicity? basicity...
24. Total force by a chain

A chain of length L,mass M kept vertical so it just touches ground.A height x of it from bottom falls down.Find the total force exerted by it on ground. My attempt: Force due to its weight=Mg Force due to falling and change in momentum: consider small element dy at height y Change in...
25. When can we conserve momentum

Hi. I found this question: A ball is suspended by a string and a bullet is shot at it from underneath.Given the masses and velocity of the bullet,can we conserve the momentum for this inelastic collision? My doubt is isn't there a vertical downward external force acting on the...

Hello all,I am having a lot of confusion about circular motion. Consider a hill which is perfectly circular at the top. When a vehicle passes over it at constant velocity,at the top most point, I want an expression for Normal reaction force by the hill on the vehicle. I take a non inertial...
27. A problem on friction

http://img600.imageshack.us/i/22258756.jpg/ link: "[URL [Broken] http://img600.imageshack.us/i/22258756.jpg/ Find acceleration of M. N1 is normal force between the two blocks and N2 is that between the ground and M. Let M move with acceleration 'a' towards right and so,m moves with...
28. Hyperbola conjugate,a>b questions

1)In a hyperbola, x^2/a^2-y^2/b^2=1(standard form), b^2=a^2(e^2-1) This is in the case where b is greater than a. But if a is greater than b? Will that hold good correctly? 2)If you consider the conjugate hyperbola(of the standard form),what will be equation relating a,b and e? Will it...
29. Doubt with power of lens with 2 media

This is more of a general question. Suppose there is a biconvex lens(Radii are R1 and R2) with Refractive index =n2,it is bounded on 2 sides by media of RI=n1,n3. Now if I have to find its focal length, 1/f=(n2-n1)/R1+(n2-n3)/R1. Is it correct? Suppose it were correct, If there is a...
30. Fluids Archimedes principle apparent weight question

Homework Statement Vessel contains water.It is placed on the pan of a physical balance.A solid(specific gravity=1) is suspended from an thread(from an independent support),such that it is immersed completely in the water. What the weight it reads? If the thread was tied to the arm of...