### CHAPTER 8:Waves

(1)               Waves transmit ________ from one place to another.
(a)    energy
(b)    mass
(c)    both
(d)    none

(2)               The waves that require a material medium for their propagation are
called .
(a)    Matter waves
(b)    Electromagnetic waves
(c)    Carrier waves
(d)    Mechanical waves

(3)               The distance between any two consecutive crests or troughs is called.
(a)    Frequency
(b)    Period
(c)    Wave length
(d)    Phase difference\

(4)               When two identical traveling waves are superimposed, the velocity of the resultant wave.
(a)    Decreases
(b)    Increases
(c)    Remains unchanged
(d)    Becomes zero

(5)               In vibrating cord the points where the amplitude is maximum, are called.
(a)    antinodes
(b)    nodes
(c)    troughs
(d)    crests

(6)               The distance between two consecutive nodes is.
(a)    λ/2
(b)    λ/4
(c)    λ
(d)    2 λ

(7)               The distance between consecutive node and antinode is.
(a)    λ
(b)    λ/2
(c)
(d)    λ/4

(8)               If stretching force is T of wire increases, then its frequency
(a)    Deceases
(b)    Increases
(c)    Remains the same
(d)    Any of above

(9)               A stationary wave is set up in the air column of a closed pipe. At the closes end of the pipe
(a)    Always an node is formed
(b)    Always an antinode is formed
(c)    Neither node nor antinode is formed
(d)    Sometimes a node and sometimes an antinode is formed

(10)           It is possible to distinguish between transverse and longitudinal waves form the property of
(a)    Refraction
(b)    Polarization
(c)    Interference
(d)    Diffraction

(11)           according to Laplace correction sound travel in air under the conditions of
(b)    isothermal
(c)    isobaric
(d)    isochoric

(12)           Sound waves do not travel in vacuum because
(a)    They are transverse waves
(b)    They are stationary waves
(c)    They require material medium for propagation
(d)    They do not have enough energy

(13)           Velocity of sound is vacuum is
(a)    332 ms-1
(b)    320 ms-1
(c)    zero
(d)    224 ms-1

(14)           Increase in velocity of sound in the air for 1oC rise in temperature is
(a)    1.61 ms-1
(b)    61.0 ms-1
(c)    0.61 ms-1
(d)    2.00 ms-1

(15)           The velocity of sound is greatest in
(a)    Water
(b)    Air
(c)    Copper
(d)    Ammonia

(16)           On loading the prong of a tuning form with wax, its frequency
(a)    Increase
(b)    Decrease
(c)    Remains unchanged
(d)    May increase or decrease

(17)           The velocity of sound in air would become double its velocity at 0oC at temperature
(a)    313 oC
(b)    586 oC
(c)    819 oC
(d)    1172 oC

(18)           The normal ear is the most sensitive in the frequency range
(a)    20,000 to 30,000 hertz
(b)    10 to 20 hertz
(c)    2000 to 4000 hertz
(d)    6000 to 8000 hertz

(19)           Ultrasonics have
(a)    Frequency in the audible range
(b)    Frequency is greater than 20 kHz
(c)    Frequency lower than 20 Hz
(d)    All of above

(20)           The periodic alternation of sound between maximum and minimum loudness are called
(a)    Silence zone
(b)    Interference
(c)    Beats
(d)    Resonance

(21)           The number of beats produced per second is equal to
(a)    The sum of the frequencies of two tuning forks
(b)    The difference of the frequencies of two tuning forks.
(c)    The ratio of the frequencies of two tuning forks
(d)    The frequency of either of the two tuning forks

(22)           Beats are the results of
(a)    Diffraction of sound waves
(b)    Constructive and destructive interference
(c)    Polarization
(d)    Destructive interference

(23)           Silence zone takes place due to
(a)    Constructive interference
(b)    Destructive interference
(c)    Beats
(d)    Resonance

(24)           Doppler effect applies to
(a)    Sound wave only
(b)    Light wave only
(c)    Both sound and light wave
(d)    Neither sound nor light wave

(25)           When the source of sound moves away form a stationary listener, then ___________occurs.
(a)    an apparent increase in frequency
(b)    an apparent decrease in frequency
(c)    an apparent decrease in wavelength
(d)    an apparent change in frequency

(26)           A simple pendulum has a bob of mass ‘m’ and its frequency is ‘f’. If we replaced the bob with a heavier one, say of ‘2m’, then what will be its new frequency?

(a)    1/4f
(b)    1/2f
(c)    f
(d)    2f

(27)           Which one is the correct relation for fundamental frequency of open and closed pipe?
(a)    fopen  =  2 f closed
(b)    f closed = 2fopen
(c)    fopen  =  f closed
(d)    f open  =  1 / f closed

(28)           In open organ pipe
(a)    Only even harmonics are present
(b)    Only odd harmonic are present
(c)    Both even and odd harmonics are present
(d)    Selected harmonics are present

(29)           Which one is the correct relation?
(a)    V Newton = V Laplace
(b)    V Newton = γV Laplace
(c)    V Newton = √γ V Laplace
(d)    V Laplace = √γ V Newton

(30)           The dimension of elastic modulus ε is
(a)    ML-1T-2
(b)    ML-2T-2
(c)    MLT-2
(d)    ML2T-2

(31)      The wave speed of a wave in terms of its wavelength l and period is:
(a) v = l T              (b) v = l T2
(c) v = l / T                        (d)  v =  T /l

(32)      In a transverse wave the distance between a crest and a trough is equal to:
(a)   l/2                  (b)   l/4
(c)   l                     (d)  2 l

(33)      In a longitudinal wave the distance between adjacent condensations is equal to:
(a)   l/2                  (b)   l/4
(c)   l                     (d)  2 l

(34)      When a transverse wave is reflected on going from a denser to a rarer medium, then at the boundary the reflected wave undergoes a phase change of:
(a)   0o                    (b)  90o
(c)  -90o                 (d)  180o

(35)      When a wave is reflected on going from a rarer to a denser medium, then at the boundary the reflected wave will undergo a phase change of:
(a)   0o                   (b)  90o
(c)  -90o                 (d)  180o

(36)      A wave has a wavelength of 1 cm and a period of  2 sec. Its wave speed is:
(a)  0.5 m/sec         (b) 5 cm/sec
(c) 2.50 cm/sec      (d)  0.5 cm/sec

(37)      If the distance between a compression and an adjacent rarefaction is 2 cm and the wave speed of the wave is 4 cm/sec, then its wavelength is
(a)  2 cm                (b)  4 cm
(c)  8 cm                (d)  ½ cm

(38)      The intensity of a wave is the transfer of
a) energy per unit area normal to direction of  wave propagation
(b)  power per unit area normal to direction of wave propagation
(c) amplitude normal to direction of the wave propagation
(d) power per unit area parallel to direction of wave propagation

(39)      Two wave trains of the same amplitude and frequency travelling in opposite directions along the same path in the same medium produce:
(a) resonance         (b) beats
(c) standing waves (d) musical notes

(40)      The speed of the transverse waves travelling in a stretched string of mass m, length l and under tension T is given by the equation
(a)         (b)
(c)         (d)

### COMMON COLLECTOR CONFIGURATION OF A TRANSISTOR

COMMON COLLECTOR CONNECTION

In  this  configuration  the  input  is  applied  between the  base  and  the  collector and  the  output  is  taken  from  the  collector  and  the  emitter.  Here  the  collector  is common to both the input and the output circuits as shown in Fig.

Common Collector Transistor Circuit

In  common  collector  configuration  the  input  current  is  the  base current  IB  and  the output current is the emitter current IE. The ratio of change in emitter current to the  change in the base current is called current amplification factor.

It is represented by

COMMON COLLECTOR CIRCUIT

A test  circuit  for determining the  static characteristic  of an NPN transistor is shown in Fig. In this circuit the collector is common to both the input and the output circuits.   To   measure   the   base   and   the   emitter   currents,   milli   ammeters   are connected in series with the base and the emitter circuits. Voltmeters are connected   across the input an…