Physics Times 07.2019

Read the assertion and reason carefully to

mark the correct options given below:

(a) If both Assertion and Reason are true and

Reasonis the correct explanation of the

Assertion.

(b) If both Assertion and Reason are true but

Reasonis not the correct explanation of the

Assertion.

(c) If Assertion is true but Reason is false.

(d) If Assertion is false but the Reason is true.

WAVES ON STRING

1. Assertion: A wave of frequency 500 Hz is

propagating with a velocity of 350 .ms^1

Distance between two particles with 60 phase

difference is 12 cm.

Reason:

2. Assertion: In a small segment of string
   carrying sinusoidal wave, total energy is
   conserved.
   Reason: The stretch in the string is maximum
   at the mean position


3. Assertion: Solids can support both longitudinal
   and transverse waves but only longitudinal
   waves can propagate in gases.
   Reason: For the propagation of transverse
   waves, medium must also necessarily have the
   property of rigidity.


4. Assertion: A standing wave pattern is formed
   in a string. The power transfer throught a point
   (other node and antinode) is zero always.
   Reason: At antinode displacement is
   maximum


5. Assertion: Velocity of particles, while
   crossing mean position (in stationary waves)

WAVES ON STRING

1. Assertion:

Reason:

2. Assertion:

Reason:

3. Assertion:

Reason:

4. Assertion:

Reason:

5. Assertion:

.

2

x 



varies from maximum at antinodes to zero at

nodes.

Reason: Amplitude of vibration at antinodes

is maximum and at nodes, the amplitude is zero,

and all particles between two successive nodes

cross the mean position together.

6. Assertion: In a stationary wave, there is no
   transfer of energy.
   Reason: There is no outward motion of the
   disturbance from one particle to adjoing
   particle in a stationary wave.


7. Assertion: The equation of a stationary wave

is 20sin cos. 4

x

y t



  The distance between

two consecutive anti-nodes will be 4 m.

Reason: The data is insufficient.

8. Assertion:Soldiers are asked to break steps
   while crossing the bridge.
   Reason: The frequency of marching may be
   equal to the natural frequency of bridge and
   may lead to resonance which can break the
   bridge.

SOUND WAVES

1. Assertion : Sound, cannot propagate in the
   vaccum.
   Reason: Sound is a square wave.
   It propagates in a medium by a virtue of
   damping oscillation.


2. Assertion:Two persons on the surface of
   moon cannot talk to each other.
   Reason: There is no atmosphere on moon.


3. Assertion: Sound would travel faster on a
   hot summer day than on a cold winter day.
   Reason: Velocity of sound is directly
   proportional to the square of its absolute
   temperature.

Reason:

6. Assertion:

Reason:

7. Assertion:

Reason:

8. Assertion:

Reason:

SOUND WAVES

1. Assertion :

Reason:

2. Assertion:

Reason:

3. Assertion:

Reason: