CSIT 1st Semester
Physics Board Question Paper 2081 Old Course

PHY 118-2081 ✡
Tribhuvan University
Institute of Science and Technology
2081
✡
Bachelor Level/First Year/First Semester/Science
Computer Science Information Technology (PHY 118)
(Physics)
(Old Course)
Full Marks:60 Pass Marks:24 Time:3 hours

Candidates are required to give their answers in their own words as for as practicable.
The figures in the margin indicate full marks

Section A
Long Answer Questions
Attempt any Two question.
[2x10=20]
1.

Use Hooke's and Newton's second law to set up differential equation for an oscillation of a spring. Find the general solution of this differential equation and hence obtain the expressions for period, velocity and the acceleration of the oscillation.

2.

Describe construction and working principal of Frank Hertz experiment. Interpret its result. What is the conclusion of Franck-Hertz experiment? Explain.

3.

Use Fermi-Dirac statistics and Maxwell-Boltzmann distribution to show the flow of electrons from junctionsn to p is equal to the flow from junctionsp to n. How electron current from p to n (due to minority carriers) is not affected by the height of the potential energy barrier? Explain.

Section B

Attempt any Eight questions

[8x5=40]
4.

Discuss magnetic dipole moment. What is its effect on atom? and on molecules? Explain.

5.

How memory and clock circuits can be made by using RTL and TTL gates? Explain.

6.

Explain Hall effect and discuss the importance of Hall voltage while manufacturing electronic devices.

7.

A children's merry-go-round of radius 4 m and mass 100 kg has an 80-kg man standing at the rim. The merry-go-round coasts on a frictionless bearing at 0.2 rev/sec. The man walks inward 2 m toward the center. What is the new rotational speed of the merry-go-round? What is the source of this energy? (The moment of inertia of a solid disk is I = mr2/2).

8.

An alpha particle is moving with a velocity v = (3 × 104i + 4 × 104k) m/sec in a region where there is a magnetic field B = (0.5 i + k) T. Find the force experienced by the alpha particle.

9.

The de Broglie wavelength of a proton is 10-13 m. Use the known values of Planck's constant and mass of the proton to find speed of the proton. Through what potential difference must the proton be accelerated to acquire such a speed?

10.

Explain why the following eigenfunction y(x) = A eikx is not acceptable solutions of the Schrodinger equation.

11.

Assuming that atoms in a crystal structure are arranged as close-packed spheres, what is the ratio of the volume of the atoms to the volume available for the simple cubic structure? Assume a one-atom basis.

12.

The output of a digital circuit (y) is given by this expression:
y = (B̄C + C̄A)(B̄A)
Where A, B and C represent inputs. Draw a circuit of above equation using OR, AND and NOT gate and hence find its truth table.