Quantum Mechanics Answers

Describe the 5 common sources of noise in communication system and explain the ways
to reduce each of them.

A linear Hermitian operator A has infinite number of eigen values ai and has a complete set of orthonormal eigen state |ai> . If the system is in a state |ψ> = |a1> +i/2 |a2> the probability of getting a value a2 for A on measurement is
Answer:0.2

a particle in cubic shaped box with infinitely hard walls whose edges are a,b&c respectively one corner of cube at origin and edges parallel to the axes the wave function of particle?

Consider a particle in a Coulomb potential in three dimensional space. In Heisenberg's picture,d/dt⟨L^z⟩=0, where L^z is the z-component of angular momentum operator. Using this information which of the following choice(s) are correct:
1.H,L^z,L^x share simulatenous eigenbasis

2.L^z,L^x share simultaneous eigenbasis

3.H,L^z share simultaneous eigenbasis

4.L^.L^,L^z,L^x share simultaneous eigenbasis

The wavefunction for a particle is defined by:
ψ(X)= [NCos(2πx/L, for –L/4≤x≤L/4
[ 0, otherwise
Determine
i) the normalization constant N, and
ii) the probability that the particle will be found between x = 0 and x = L / 8.

Three Identical spin-half fermions are to be distributed in two non-degenerate distinct energy levels. The number of ways this can be done is.
1)8
2)4
3)3
4)4

What should the nature of the wave function be used to represent an electron in a crystalline solid?

When an object of mass 200g is submerged in methanol, its apparent weight is 1.052N. When submerged in benzene, its apparent weight is 0.951N. if the density of methanol is 0.8g/cm3, what is the density of benzene?

The massless spring of a spring gun has a force constant k = 0.04 N/cm. When the gun is aimed vertically, a 30 g projectile is shot to a height of 5.0 m above the end of the expanded spring. How much was the spring compressed initially? (Find d, in meters.)

In the Large Electron Positron collider at CERN (an experiment which ended in the year 2000), groups
of electron and positrons were accelerated along a circular tunnel, so that they collided.
Electromagnets were used to keep the particles moving in a circle. Discuss how the strength and
direction of the magnetic field would need to be adjusted to:
i) keep a particle travelling in a circle while it is increasing its speed
ii) bend the paths of both positrons and electrons which are travelling in opposite directions in the same tunnel