Physics full notes of class 11 ch8
The correct answers with their questions numbers.
1 = A , 2 = B , 3 = C , 4 = A , 5 = D , 6 = B , 7 = B , 8 = B , 9 = D , 10 = D , 11 = A , 12 = A , 13 = D
Physics full notes of class 11 ch8 Mcqs end.
Question 1 Answer: Progressive waves: The waves which are produced in a medium and they travels from one point to the other are known as progressive waves or travelling waves.
For example , When a pebble is dropped into a pond of water then waves are produced due to disturbance towards the edge of the pond. These waves transfer energy from one place to another and are called progressive waves.
Stationary (OR) Standing waves: These waves are formed when two exactly similar waves are travelling in opposite direction consists of nodes and antinodes which are produced one after the other in a certain order nodes the amplitude of vibration is zero and thus the stationary waves cannot transfer energy from one place to another.
Question 2 Answer: Transverse waves:
A. In transverse waves the particle of the medium vibrate perpendicularly to the direction of propagation of the waves.
B. The transverse waves consists of crests and trough.
C. The distance between two consecutive crests and two consecutive troughs is equal to |/2.
D. The transverse waves can propagate in solids and at the surface of liquids only.
E. There is no pressure varations.
F. Water waves, waves produced in a stretched string etc are the examples of transverse waves.
A. In longitudinal waves the particle of a medium vibrate parallel to the direction of propagation of the waves.
B. The longitudinal waves consists of compresstions and rarefaction.
C. The distance between two consecutive compression or two rarefactions is equal to |/2.
D. The longitudinal waves can propagate in solids, liquids as well as in gases.
E. The pressure is maximum at compressions and minimum at rarefactions.
F. Sound waves , Earth quake waves etc are the examples of longitudinal waves.
Question 4 Answer: There is no transfer of energy through a medium when a stationary wave is produced in it.
We know that stationary waves consists of nodes at which the amplitude of vibration is zero i-e these points are at the rest and their displacements from mean position are zero. Thus the energy can not transfer through a medium when a stationary wave is produced in it. Only interconversion of kinetic energy and potential energy occurs at anti nodes.
Question 5 Answer: When two similar wave pulses are traveling in opposite direction and they superpose each other, then standing waves are produced. The standing waves consists of nodes and anti nodes. At node the amplitude of vibration is zero i-e the particles of the medium remains at rest at the nodes. So there is no transfer of energy through the medium due to nodes. However only the interconversion of kinetic energy and potential energy takes place. At anti nodes the energy is potential while at mean position the energy is kinetic.
Question 8 Answer: Yes it is possible for an object which is vibrating transversely to produce sound wave. All the stringed and percussion instruments when played produces transverse waves. And the energy from these vibrating instruments travels through air in the form of sound waves which are longitudinal waves in nature.
Question 11 Answer: It is not possible for two astronauts to talk directly to one another even if they remove their helmets. It is because the sound are longitudinal mechanical waves which need a material medium for their propagation. As there is no material medium between the two astronauts , so they can not talk directly to one another.
Physics full notes of class 11 ch8 short questions end.