question paper

1. GOVERNMENT POLYTECHNIC COLLEGE, PALA
MODEL EXAMINATION IN DIPLOMA OF ENGINEERING - MARCH 2020
ENGINEERING PHYSICS II (Common to all branches)
Time : 3 hour Maximum Marks : 100
Part A
I. Answer the following questions. Each carries 2 marks (Maximum Marks: 10)
1. Define Moment of inertia? Give its unit and dimensional Formula?
2. Describe the laws of photoelectric effect?
3. State Newton’s law of gravitation with formula?
4. What are the advantages of gas lasers over solid state LASERS?
5. What is neutron multiplication factor? Give its significance?
Part B
II.Answer any five of the following questions. Each carries 6 marks (Maximum Marks: 30)
1. The work function of a metal is 2.8 eV. What is its threshold wavelength?
2. How much energy will be produced in the fission of 1gm of uranium if 0.1% of the mass is
converted into energy in the fission process?
3. A wire of infinite length carries a current 5 A. Find the magnetic field due to the whole length
of the wire at a perpendicular distance of 20 cm from the wire?
4. The resistance of a copper wire of length 100 m and radius 0.3 mm is 6 ohms. Calculate the
resistivity of copper?
5. If the escape velocity of a body from the moon is 2.4 km/s and radius of the moon is 1750 km,
calculate the acceleration due to gravity on the surface of the moon?
6.A circular disc of mass 40 gm rolls along the ground with a velocity 0.4 m/s. Calculate its
total kinetic energy?
7. A particle moves in a circle of radius 20 cm with speed 10 m/s. Find its angular velocity?
Part C
Answer one full question from each unit. Each full question carries 15 marks
UNIT I
III a) What is meant by angular velocity? Derive the relation between linear velocity and angular
velocity for uniform circular motion?
b) Derive an expression for the moment of inertia of a uniform circular disc about an axis
passing through its centre and perpendicular to its plane?
c) State and explain parallel and perpendicular axes theorem?
OR

2. 1V a) Derive the moment of inertia of a ring a) about an axis through its centre and
perpendicular to its plane ? and b) about a tangent?
b) Obtain an expression for centripetal acceleration of a body?
c) What is meant by banking of curved tracks? Write an expression for the height of banking
in curved railway tracks?
UNIT II
V a) What is orbital velocity? Derive the expression for the orbital velocity of a satellite
revolving round the earth at a distance h from the surface of the earth?
b) What are geostationary satellites? Describe its applications?
c) What is escape velocity? Derive its value for a mass m situated on the surface of the earth?
OR
VI a) Describe the variation of acceleration due to gravity with a) altitude B) depth and c)
Latitude?
b) Compare between Polar and GPS satellites?
c) Derive the period of revolution of a satellite?
UNIT III
VII a) State and explain Biot Savart’s Law? Use Biot Savart’s law to find the magnetic field at
the centre of a circular coil?
b) State Fleming’s left hand rule? Give expression for the force on a current carrying
conductor placed in a magnetic field.
c) What is a shunt? What is its use in an ammeter?
OR
VIII a) State Ohm’s law? Describe the laws of combination of resistances?
b) State and explain Kirchoff’s laws? State the Right hand grip rule?
c) Describe with necessary theory the construction and working of a moving coil
galvanometer?
UNIT IV
IX a) What are the essential components of a nuclear reactor? Explain the functions of each?
b) What is a LASER? Give the principle of operation of a LASER?
c) Describe photoelectric equation? Explain the terms work function and threshold
frequency?
OR
X a) With a neat diagram explain the construction and working of a He-Ne LASER?
b) Explain photoelectric effect? What is a photo electric cell? Give applications?
c) Distinguish between Nuclear fission and Fusion?