Hall Ticket No Question Paper Code: AHS007
INSTITUTE OF AERONAUTICAL ENGINEERING
(Autonomous)
B.Tech I/II Semester Supplementary Examinations July, 2017
Regulation: IA-R16
APPLIED PHYSICS
[Common for I Semester ME and
Time: 3 Hours Max Marks: 70
Answer ONE Question from each Unit
All Questions Carry Equal Marks
All parts of the question must be answered in one place only
UNIT I
1. What is electronic polarization? Show that electronic polarisability is directly proportional to
the cube of the radius.
The electronic polarizability of He gas is 2:24310􀀀41Fm2. If the gas contains 2:71025 atoms
per m3 at NTP, calculate dielectric constant of He gas.
2. Classify different magnetic materials diamagnetic paramagnetic and ferromagnetic based on
their magnetic moments. Discuss different properties exhibited by them with examples.
A paramagnetic material has a magnetic field intensity of 104 A/M. If the susceptibility of the
material at room temperature is 3:7 calculate the magnetization and flux density in the
material.
UNIT II
3. What is absorption coefficient? What is its unit? Derive an expression for absorption coefficient
of a material.
The volume of a room is 1200 m3. The wall area of the room is 220 m2, the floor area is 120 m2
and ceiling area is 120 m2. The average sound absorption coefficient
i. for wall is 0.03,
ii. for ceiling 0.80 and
iii. for floor is 0.06.
Calculate the average sound absorption coefficient and reverberation time of the room.
4. What is piezo electric effect? Explain how it is useful in the construction of an ultrasonic oscillator.
Give some of the uses of ultrasonic wave.
A piezo electric crystal has a thickness 0.002 m. If the velocity of sound wave in crystal is 5750
calculate the fundamental frequency of crystal.
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UNIT III
5. State Lami's theorem, which gives condition of equilibrium of three coplanar force systems. Also
prove this theorem.
Three forces acting at a point are in equilibrium. If they make angles of 120 with one another,
show that they are equal.
6. State the triangle law of forces. A car accelerates uniformly from rest and acquires a speed of 36
km/h in 10 sec. Calculate
i. the acceleration
ii. total distance travelled
iii. the speed at the end of 5th second
iv. the distance travelled in 5th second.
Discuss the couple, considering the two parallel coplanar forces of system.
UNIT IV
7. What is limiting friction?A block is placed on an inclined plane. The plane is then raised until
it makes an angle with the horizonatal. If for block and plane is 0.3. Find value of angle
to which the plane may be raised before the block beings to inside.
Derive the relation between angle of friction and coefficient of friction.
8. A body of mass m slides down a rough inclined plane at an angle with horizontal. If is the
coefficient of kinetic friction then find an expression for the acceleration of the body.
A block slides down an inclined plane of angle 30 with horizontal with an acceleration g/4. Find
the coefficient of kinetic friction.
UNIT V
9. A circular disk has mass of 1 kg and diameter of 15 cm. Calculate its moment of inertia about a
tangent perpendicular to the plane and a diameter.
Obtain an expression for moment of inertia rectangular lamina about axis passing through its
centre and parallel to one of the side.
10. State and prove theorem of perpendicular axis.
A flywheel is a uniform disc of mass 72 Kg and radius of 50 cm. calculate
i. Moment of inertia.
ii. its kinetic energy when it is rotating at 70 r.p.m.