ASSCERTION (MCQ) - ONE MARK QUESTIONS
For question numbers 11, 12, 13, 14 and 15 two statements are given-one labeled Assertion (A) and the other labeled Reason (R). Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.
a) Both A and R are true and R is the correct explanation of A
b) Both A and R are true but R is NOT the correct explanation of A
c) A is true but R is false
d) A is false and R is also false
(11) ASSERTION (A):- Material particles have wavelength. [ ]
REASON (R); - Because of de Broglie’s Hypothesis.
(12) ASSERTION(A):- The objective of telescope has smaller focal length [ ]
Than eye piece.
REASON (R):- To collect more radiation.
(13) ASSERTION(A) :- Wave effects of light are not considered in day to [ ]
Day life.
REASON (R):- Because Fresnel distances for apertures are large.
(14) ASSERTION (A):- Ray optics is valid to infinity. [ ]
REASON ( R):- Because light rays travel to infinity.
(15) ASSERTION (A):- In refraction velocity of light changes. [ ]
REASON (R):- Because its frequency changes.
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Answers
Answer:
Answer. Answer: (a) Both assertion and reason are true and reason is correct explanations of the assertion.
12) The focal length of the objective in a telescope is larger than that of eyepiece.The objective is a convex lens of large focal length and large aperture. It usually made of two convex lenses in contact with each other to reduce the chromatic and spherical aberrations.The eye piece is also a convex lens .Its focal length is smaller than that of objective. It is also a combination of two lenses.
Magnifying power of telescope increases when the aperture of the objective is large
a) In a single slit diffraction experiment, if the width of the slit is made double the original width, then the size of the central diffraction band reduces to half and the intensity of the central diffraction band increases up to four times.