Home
Class 12
PHYSICS
Answer the following questions : (a) W...

Answer the following questions :
(a) When a low flying aircraft passes overhead, we sometimes notice a slight shaking of the piture on our TV screen. Suggest a possible expanation.
(b) As you have learnt in the text, the principle of linear superposition of wave displacement is basic to understanding intensity distributions in diffractions and interference patterns. What is the justification of this principle ?

Text Solution

Verified by Experts

(a) A low-flying aircraft reflects the TV signal by its metallic body. Interference between the the direct signal received by the antenna and the reflected signal from the aircraft causes the slight shaking of the picture on our TV screen.
(b) Superposition principle follows from the nature of the (differential) equation governing wave motion. It is true so long as wave have small amplitude.
Promotional Banner

Topper's Solved these Questions

  • WAVE OPTICAL

    MODERN PUBLICATION|Exercise NCERT (EXemplar Problems Obejective Questions) (Multiple Choice Questions (Type-I)|5 Videos

  • WAVE OPTICAL

    MODERN PUBLICATION|Exercise NCERT (EXemplar Problems Obejective Questions) (Multiple Choice Questions (Type-II)|4 Videos

  • WAVE OPTICAL

    MODERN PUBLICATION|Exercise NCERT FILE SOLVED (TEXT BOOK EXERCISES)|10 Videos

  • SEMICONDUCTOR ELECTRONICS METERIALS DEVICES AND SIMPLE CIRCUITS

    MODERN PUBLICATION|Exercise CHAPTER PRACTICE TEST FOR BOARD EXAMINATION|12 Videos

Similar Questions

Explore conceptually related problems

What is the reason behind the disturbing of incoming and reflected signals when a low flying aircraft passes overhead, which results in slight shaking of the picture on our TV screen ?

Answer the following questions (a) In a single slit diffraction experiment, the width of the slit is made double the original width. How does this affect the size and intensity of the central diffraction band? (b) In what way is diffraction from each slit related to the interference pattern in a double-slit experiment? (c) When a tiny circular obstacle is placed in the path of light from a distant source, a bright spot is seen at the centre of the shadow of the obstacle. Explain why? (d) Two students are separated by a 7 m partition wall in a room 10 m high. If both light and sound waves can bend around obstacles, how is it that the students are unable to see each other even though they can converse easily (e) Ray optics is based on the assumption that light travels in a straight line. Diffraction effects (observed when light propagates through small apertures/slits or around small obstacles) disprove this assumption. Yet the ray optics assumption is so commonly used in understanding location and several other properties of images in optical instruments. What is the justification?

Answer the following questions : (a) You have learnt that plane and convex mirrors produce virtual images of objects. Can they produce real images under some circumstances ? Explain. (b) A virtual image, we always say, cannot be caught on a screen. Yet when we see a virtual image, we bring it to screen i.e. retine of our eye. Is there a contradiction ? ( c) A diver under water looks obliquely at a fisherman standing on the bank of a lake. Would the fisherman look taller or shorter than what he actually is ? (d) Does the apparent depth of a tank of water change if viewed obliquely ? If so, does the apparent depth increase or decrease ? ( e) The refractive index of diamond is much greater than that of ordinary glass. Is this fact of some use to a diamond cutter ?