Question 11:
easyAssertion (A): Law of reflection is applicable for all type of mirrors.
Reason (R): Rays which are parallel to the principal axis are known as paraxial rays.
Assertion (A) is true. The laws of reflection hold for all types of mirrors.
Reason (R) is false. Paraxial rays are rays close to and making small angles with the principal axis; not all parallel rays are paraxial, nor are all paraxial rays parallel to the axis.
Hence, (A) is true and (R) is false.
Question 12:
easyAssertion (A): When an object is placed between two plane parallel mirrors, all the images formed are of equal intensity.
Reason (R): In above situation of two plane parallel mirrors, only two images are possible.
Assertion (A) is false. Image intensity decreases with each reflection due to absorption.
Reason (R) is false. An infinite number of images are formed between two parallel plane mirrors.
Therefore, both (A) and (R) are false.
Question 13:
easyA tall man of height 6 feet, want to see his full image. Then required minimum length of the mirror will be:
(2000)
For a person to see their full, complete image in a vertical plane mirror, the minimum length of the mirror required is exactly half of the person's height, regardless of their distance from the mirror. Therefore, minimum length = $6 / 2 = 3 feet$ .