Physics full notes of class 11 ch9
The correct answers with their questions numbers.
1 = A , 2 = D , 3 = C , 4 = B , 5 = C , 6 = B , 7 = D , 8 = B , 9 = C , 10 = C , 11 = C , 12 = C
Physics full notes of class 11 ch9 Mcqs end.
Question 1 Answer: When the soap bubble is about to break the thickness of the soap film becomes too small i-e almost equal to zero. So the path difference between the two parts of the beam is zero. As one part of the beam is reflected from teh denser medium (upper surface) , there fore a path difference of ‘|/2’ occurs for ray ‘I’ and the second ray is reflected from a rare medium (lower surface) , so there is no path difference for it. Now the total path difference between first ray and the second ray become’|/2′ due to which destructive interference takes place and as a result the soap bubble looks block.
Question 3 Answer: In a michelson interferometer a second glass plate is used to introduced in beam ‘1’ by its two passages through first plat ‘A’ . So the path difference between the two beams of light is zero and as a result constructive interference occurs due to which we can observe bright fringes with the help of telescop.
Question 6 Answer: The wave trains from the two separate head lamp are differ in phase. Their phase difference is not satisfied. Also these sources are not monochromatic. Due to these reasons, it is not possible to see the interference where the light beams from the head lamps of a car overlap.
Question 7 Answer: The sound light both are waves. But the wavelength of sound waves is very large as compared to the wave length of light waves. Hence the sound waves are bent round corners of the pole. So they are heard.
On the otherhand , the wave length of light wave is not comparable to the dimensions of the pole and therefore it is not diffracted. thus the light waves can not be observed around the corners.
In Youngs double slit experiment double slits are used to observe inteference phenomenon for visible light. The x-rays are electromagnetic wave having very short wave length (10 power-10 m) as compare to visible light. Therefore they do not show diffraction effect by using ordinary diffracting objects like slits, sharpe edge objects, diffraction grating etc. As in youngs double slit experiment an ordinary diffracting objects i-e slits are sued so it is not possible to obtained the diffraction of x-rays by youngs double slits experiment.
Question 9 Answer: The hygens principal tell us that how the wavelength propagate in the space from point to point. So we can apply the hygens principle to radar waves.
Physics full notes of class 11 ch9 short questions end.