## 13 April 2010

### Properties of Matter and Sound

UNIT – I ELASTICITY
1. The driving shaft of an automobile is in the form of a tube rather than a solid rod of the
same mass because
a. couple per unit twist can be smaller for them b. couple per unit twist is larger
c. longitudinal strain is larger for tuber d. solid rods will be heated up easily
2. The period of oscillation of a torsion pendulum is independent of
a. its mass b. rigidity modulus of the wire c. acceleration due to gravity at the place
d. the dimensions of the oscillating body
3. If the diameter of the suspension wire is doubled without changing the length in case
of a torsional pendulum, the time period
a. will increase b. will not be affected c. will decrease d. will double
4. The bending moment produced in a beam depends upon
a. Young’s modulus of the beam b. Geometric MI of the cross-section of the beam
c. radium of curvature of the neutral axis d. all the above
5. The elevation at the centre (y) in the case of uniform bending and the Young’s modulus “q” are related by a. y a q b. y a 1/q c. y a q2 d. y a 1/q2
6. When a bar is bent non-uniformly, the central depression is
a. directly proportional to Young’s modulus b. equal to Young’s modulus
c. inversely proportional to Young’s modulus d. none of the above
7. The depression at the centre of a given beam supported on two knife-edges and loaded
in the middle varies ___________ of the distance between the two knife-edges.
a. directly as square b. directly as cube c. inversely as square d. inversely as cube
8. For a beam of rectangular cross-section the depression (d) at the middle is related to
the thickness (d) of the beam as
a. d a 1/d b. d a 1/d2 c. d a 1/d3 d. d a d3
9. The work done in twisting the wire is stored up in the wire as __________
a. potential energy b. KE c. Electrical energy d. mechanical energy
Answers : 1) b 2)c 3) c 4) d 5) b 6) c 7) b 8) c 9) a
UNIT – II - SURFACE TENSION
1) When there are no external forces, the shape of a liquid drop is determined by
a) Surface tension of the liquid b) Density of the liquid
c) Viscosity of liquid d) Temperature of air only
2) Angle of contact for a liquid that does not wet the solid which is in contact with it, is
a) greater than 90° b) greater than 180° c) less than 90° d) zero
3) A liquid rises in a capillary tube when the angle of contact is
a) An acute angle b) An obtuse angle c)  radian d)  /2 radian
4) Tip of the nib of a pen is split. It is because
a) The ink may come in contact with the air of atmosphere
b) The ink may rise by capillary action c) Neither a or b d) of gravitational pull
5) When two capillary tubes of different diameters are dipped vertically, the rise of the
liquid is
a) same in both the tubes b) more in tube of larger diameter
c) less in tube of smaller diameter d) more in the tube of smaller diameter
6) The cotton wick in an oil filled lamp keeps on burning because
a) in the cotton wick there are innumerable capillaries in which oil continues to rise
b) cotton wick is a good conductor of heat
c) cotton wick is a semi permeable membrane d) none of these
7) On breaking a capillary tube in which a liquid has risen to the maximum height, it will
be noticed that the
a) liquid will overflow in the form of a fountain b) liquid will not overflow
c) liquid will trickle down the edges d) liquid will reach a new height
10) Dimensional formula for surface tension is
a) MT-2 b) MLT-2 c) ML-2T-2 d) M-1T-2
1) a 2) a 3) a 4) b 5) d 6) a 7) b 8) a
Viscosity
1. Viscosity is the property by virtue of which a liquid
a) occupies minimum surface area b) opposes relative motion between its layers
c) becomes spherical in shape d) tends to regain its deformed position
2. The viscous force between two liquid layers is
a) radial b) normal to the liquid surface c) tangential to the liquid surface
d) neither purely tangential nor purely normal
3. When a fluid is in stream line flow, then the reason of viscous force acting between its
two layers is
a) transport of energy from one layer to another b) transport of linear momentum
from one layer to another c) same velocity of molecules d) the variable density
along the length of the tube
4. The profile of advancing liquid through a tube is
a) straight line b) hyperbola c) parabola d) semicircle
5. The velocity of flow at a distance x from the axis of tube
a) increases as x increases b) decreases as x increases c) remains constant
d) depends on the length of the tube
6. The ratio of radii of two spheres is 1:2. When they are dropped in a viscous liquid, the
ratio of their terminal speeds is
a) 1:1 b) 2:1 c) 1:2 d) 1:4
7. A small spherical liquid drop is moving in a viscous medium. The viscous force does
not depend on
a) nature of the medium b) density of the medium
c) the instantaneous speed of the spherical drop d) the radius of the spherical drop
8. Viscosity in fluid motion is analogous to
a. friction in the motion of solids b. random motion of the gas molecules
c. non-uniform motion of solids d. internal motion
9. The terminal velocity of small sized spherical body of radius r falling vertically in a
viscous liquid is given by the following
a. 1/r2 b. 1/r c. r d. r2
10. The unit of coefficient of viscosity is
a. Nsm-2 b. Ns2m-2 c. N3sm-2 d. None of these
11. The dimensions of velocity gradient is
a. T2 b. T-1 c. T4 d. T-2
12. For narrow tubes, the value of k is
a. 3000 b. 5600 c. 1000 d. 2000
1) b 2) c 3) b 4) c 5) b 6) d 7) b 8) a 9) d 10) a 11) b 12) c
UNIT – III DIFFUSION AND OSMOSIS
1. The time of diffusion from one distribution of concentration to another, in a given
solution is directly proportional to the
a. length of its column b. square of the length of its column
c. cube of the length of its column d. square root of the length of its column
2. There is a close analogy between the process of diffusion of a solute and the
a. flow of heat through a solid b. flow of liquid through a capillary tube
c. rise of liquid in a capillary tube d. none of the above
3. The rates of diffusion of two gases are
a. directly proportional to their densities b. inversely proportional to their densities
c. inversely proportional to the square roots of their densities d. none of the above
4. The process of inter-diffusion of two liquids through a membrane is called
a. viscosity b. surface tension c. diffusion d. osmosis
5. Crystalloids diffuse ________ than colloids.
a. slower b. faster c. some time slower d. none of the above
6. For a given solution, the rate of diffusion is directly proportional to its ________
a. concentration b. density c. pressure d. temperature
7. The unity of diffusivity is a. m2s-1 b. m3s2 c. ms-4 d. none
8. The dimensional formula for diffusivity is
a. L3T-1 b. L2T-1 c. L4T2 d. LT-2
9. The rate of diffusion of a gas in inversely proportional to the square root of its _______
a. pressure b. density c. temperature d. concentration
10. Osmosis is a ________________ phenomenon
a. selective b. more general c. both a and b d. none of the above
1) b 2) a 3) c 4) d 5) b 6) a 7) a 8) b 9) d 10) a
UNIT – IV - GRAVITATION
1. If the distance between two masses is doubled, the gravitational attraction between
them
a. is doubled b. become four times c. is reduced to half d. is reduced to a quarter
2. Newton’s law of gravitation applies to
a. small bodies only b. planets only c. both small and big bodies d. solar system only
3. If a body describes a circular motion under inverse square field, the time taken to
complete one revolution T is related to the radius of r of the circular orbit as
a. T is directly proportional to r b. T is directly proportional to r2
c. T2 is directly proportional to r3 d. T is directly proportional to r4
4. The orbital speed of Jupiter is
a. greater than the orbital speed of earth b. less than the orbital speed of earth
c. equal to the orbital speed of earth d. zero
5. If the mass of a planet is doubled and radius is halved, the acceleration due to gravity
becomes _________the original value
a. 8 times b. equal c. 4 times d. 2 times
6. If the radius of earth were to shrink by one percent, its mass remaining the same, the
acceleration due to gravity on the earth’s surface would
a. decrease b. remain unchanged c. increase d. none of the above
7. How many times faster than the present speed should the earth rotates about its axis in
order that an object placed at the equator may just fly off?
a. 111.3 times b. 17times c. 9.8 times d. 3×1010 times
8. If the earth stops rotating, the value of “g” at the equator will
a. increase b. remain same c. decrease d. none of the above
9. The unit of G is a. Nm2Kg-2 b. N2m2Kg-2 c. Nm-2Kg-2 d. N-1m-2Kg-2
10. The dimension of G is a. M-1L3T-2 b. M-2L3T-2 c. M-1L2T-2 d. none
11. Any rigid body capable of oscillating freely about a horizontal axis passing through it
is a _________
a. Torsion pendulum b. Compound pendulum c. Rigid pendulum d. none
1) d 2) c 3) c 4) b 5) a 6) c 7) b 8) a 9) a 10) a 11) b
UNIT – V - SOUND
1. Sound of each syllable should soon decay so that the succeeding syllable may be heard
distinctly. This means that the auditorium must be free from
a) excessive reverberation b) Echos c) silence d) none of these
2. The acoustics of an auditorium can be improved by using the surfaces with high
absorption coefficient. This will reduce the reverberation time below the
a) optimum value b) acoustic value c) critical value d) none
3. The human ear is sensitive to sound waves in the frequency range from
a) 50 to 50,000Hz b) 80 to 80,000Hz c) 20 to 20,000Hz d) 100 to 10,000Hz
4. Sound waves of frequency more than 20,000Hz are called
a) Acoustic wave b) Ultrasonics c) Transverse wave d) none of these
5. Ultrasonics waves travel with the speed of
a) sound b) light c) both a and b d) none of these
6. Just like ordinary sound waves, ultrasonic waves get
a) reflected b) refracted c) absorbed d) both a, b and c
7. Ultrasonic waves ________ crystalisation
a) accelerate b) does not accelerate c) accelerate under special condition
d) both a and c
8. The ultrasonic waves will have wavelengths of _________
a) 1.65cm and above b) 1.65cm and less c) -1.65cm and less d) none
9. If an arrangement is made to form stationary waves of ultrasounds in a liquid, it
serves as a diffraction grating. It is called an ____________
a) acoustic grating b) multistage grating c) monomer grating d) none