, 8  2017
State Dalton’s law of
partial pressures?
a The total pressure of a
mixture of ideal gases is the
sum of partial pressures.
This is called Dalton's law
of partial pressure
29) When does a real gas
behaves like an
23

28)
ideal gas?.
a At low pressure and high
temperature
real gases
behave like an ideal gas.
30) Thermos flask containing
a liquid is shaken vigo rously .,what happens to
its temperature?
a Flask is an isolated system.
Heat is not exchanged
between
system
and
surroundings ,so when the
flask is shaken vigorously
the kinetic energy of
molecules increases there by
internal energy as well as
temperature increases by a
little.
Why are drops and Bubbles spherical?
PHYSICS
PEESARI SRINIVAS
SENIOR.PHYSICS
FACULY
HYD. 97007 24464
Very short answer type questions
1) What is the discovery of CV Raman?
a CV Raman discovered Raman effect. it
deals with the scattering of light by
molecules of a medium when they are
excited to vibrational energy levels.
2) What is the contribution of s
Chandrasekhar to Physics?
a He explained Chandrasekhar limit, he
worked on the structure and evolution of
stars.
3) Distinguish between accuracy and
precision?
a Accuracy of a measurement is a measure
of how close the measured value is to the
true value all the quantity. where as
Precision tells us to what resolution or limit
the quantity is measured. It depends on the
resolution of the measuring device
4) Distinguish between fundamental units
and derived units.?
a Units of the fundamental physical
quantities such as length ,mass, time are
known as fundamental units. Units of the
derived physical quantities such as velocity
,force, energy are known as derived units
5) How can systematic errors be minimised
are eliminated?
a Systematic errors can be minimised by
improving experimental techniques, selec
-ting better instruments and removing
personal bias as far as possible
6) The states of motion and rest or relative.
Explain?
a A man sitting in a moving train is at rest
with respect to his co passengers ,but he is
in motion with respect to the objects
outside the train .Hence rest and motion are
relative terms
7) What is inertia? What gives a measure
of inertia?
a The inability of the body to change its state
of rest or of uniform motion by itself is
called inertia. mass is the measure of
inertia.
8) When a bullet is fired from a gun, the
gun gives a kick in the backward
direction explain?
a According to law of conservation of
momentum when a bullet is fired from the
momentum of the gun is equal and
opposite to that of bullet as the bullet
moves forward on firing a gun moves back
9) Why does the car with flattened tyre
come sooner than the one with
inflattened tyre?
a In case of flattened tyres more formation
occurs when compare to that of inflattened
tyres.since rolling friction is directly
proportional to the area of contact.
Flattened tyres stop sooner than that of
inflattened tyre.
Jr.Inter
SPl
10) What happens to the coefficient of
friction if the weight of the body is
doubled?
a Coefficient of friction is independent
of weight of the body so coefficient of
friction remains constant.
11) Is it necessary that a mass should be
present at the centre of mass of any
system?
a It is not necessary to have any Mats at
the centre of mass ,for example the
circular ring has centre of mass at its
Centre ,where there is no mass
12) Why are spokes provided in a bicycle
wheel?
a To reduce the Jerks in the cycle the
moment of inertia is increased to
maximum possible value for minimum
possible weight. A large moment of
inertia is obtained by putting more
mass far away from axis, so spokes are
fitted in the cycle wheel
13) Why should a helicopter necessarily
have two propellers?
a If the helicopter had only one
propeller, then due to conservation of
angular momentum helicopter itself
would turn in the opposite direction
14) What are polar satellites?
a A satellite that revolves in a polar orbit
is called a polar satellite. polar Orbit
passes over North and South poles of
the earth and has a smaller radius 500
to 800 kms
15) Hydrogen is in abundance around
the sun but not around the earth,
explain?
a The RMS velocity of hydrogen
molecule at ordinary temperature is
around 2 km/s , escape velocity on the
sun(620km/s) is greater than escape
velocity on the earth(11.2km/s) the
gravitational attraction of the sun is
more than the earth .hence hydrogen is
in abundance around the sun and less
around the earth
16) State hook’s law of elasticity?
a With in the elastic limit the stress is directly
proportional to strain I .e stress=E(strain),
here E is called modulus of elasticity
17) What are the theoretical and practical
values of poisson’s ratio?
a Theoretical limits of poisson ‘s ratio: -1 to.
0.5. Practical limits of poisson’s ratio:0 to
0.5
18) State the examples of nearly perfect elastic
and plastic bodies?
a Nearly perfect elastic bodies are quartz and
phosphor bronze. Nearly perfectly inelastic
bodies are clay ,putty ,butter
19) Why are drops and Bubbles spherical?
a Due to surface tension raindrops are
spherical. Surface tension keeps the surface
area minimum. For a given volume The
sphere has minimum surface area. Hence
raindrops and bubbles are spherical in
nature.
20) Give the expression for the excess
pressure in a soap bubble ?
a Excess pressure in soap bubble in air,
Δp = 4s. where s is surface tension and r is
radius of the soap bubble.
21) Distinguish between heat and
temperature?
a Heat is a form of energy that flows between
the body and the surrounding medium by
virtue of temperature difference between
them. Temperature is a quantitative
representation of the degree of hotness of
coldness of a body.
22) Why gaps are left between rails on a
railway track?
a To Allow the expansion of the rain in
summer due to rise of temperature ,a small
gap should be left between rails
23) Why utensils are coated black?. Why the
bottom of utensils are made of copper?
a As the block is a good observer of heat,
utensils are coated black to provide heat to
the cooking substance. Bottom of the
utensils are made of copper ,because
copper is good conductor of heat and it
promotes the distribution of heat over the
bottom of a vessel for uniform cooking
24) State wein's displacement law?
a In thermal radiation as the temperature of
the body increases, the wavelength
corresponding to maximum energy
decreases
25) Ventilators are provided in rooms just
below the roof why?.
a Ventilators are provided in rooms just
below the roof because the hot air escapes
out to the ventilator and fresh air enters the
room through the door and the windows.
26) The roof of building are often painted
white during summer. Why?
a Poor absorbers are poor emitters. The roof
of building is painted white, so that it
absorbs less radiation ,so we feel cool in
house ,so we feel cool in house
27) What is mean free path?
a The average distance a molecule can travel
between two successive collisions is called
mean free path.
 

‘ -2017’
a
a
a
    . 
   
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.
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