Question

The question given below consists of statements of an assertion and a reason.
use the following key to choose the appropriate answer.[Q.No 1 and 2]
(A) if if both assertion and reason are correct and reason is the correct explanation of the assertion
B) if assertion is correct but reason is not the correct explanation of the assertion
C) if assertion is correct but reason is incorrect
D) if both assertion and reason are incorrect
1. assertion : the mirrors used in search Lights Are parabolic and not concave spherical
Reason: in a spherical mirror the image formed is always virtual
2. Assertion : for observing traffic at or back we prefer a convex mirror
Reason : a convex mirror has a larger field of view than a plane mirror or a concave mirror

Answer 1

1) The mirrors used in search lights are parabolic and not concave because when the light coming the source at focus, falls on a parabolic mirror the reflected light passes parallel over the entire cross section of the mirror

2) For observing traffic at or back we prefer convex mirror because it has a larger field of view than a plane mirror or a concave mirror

Hence, for the Q. no 1 option B is the right answer,

while for Q. no 2 option A is the right answer

Note:

If we used a concave spherical in place of parabolic mirror for the search lights then the source placed at the focus of concave spherical produces light which in turn causes a parallel beam of light only for par-axial rays while the marginal rays give a divergent beam, due to large aperture. Hence leads to reduction in the intensity of light. And hence, it doesn't properly serve the purpose of a search light.

Answer 2

Answer:

For 1 answer is c because concave mirror may form virtual or real image both .

Explanation:

For 2 the answer is a