Question

(A) If both assertion and reason are correct and reason is the correct explanation of assertion. (B) If both assertion and reason are true but reason is not the correct explanation of assertion. (C) If assertion is true but reason is false. (D) If assertion is false but reason is true. Assertion: A parallel beam of light is incident on a thin convex lens and is also parallel to the principal axis of convex lens as shown. The magnitude of deviation of each ray of this beam produced by given convex lens is different. parallel beam of light principal axis Reason: A thin convex lens can be assumed to be made of prisms of small angles. The magnitude of deviation produced by prism of small angle for small angles of incidence depends on angle of prism. Each ray of the beam in situation of statement-1 is incident on a prism of different angles, hence the magnitude of deviation for each ray is different. OA c B D 0

Answer 1

optim A is correct answer. We can explain in this way. For priam, angle of dariation 8= i, -r, +18 = li ti,- (hitre) [from AO MR, outer angle, is canal to to internal angle foro quadrilateral A QOR А P 8 P S B c - 360 LA TERGO+CO Rotlo =) Le tco = 360-180 - 180' Cas No f PR are normal to the triom surface Anagro LROO+LQ Rotco = 180 7) = 180' ritr to

Comparing ean ☺ f LA = Nitra A is the angle of frism So, 8 = - A where dit iz For prism, Suppose light is incident at a small angle is on the frism tas angles rir, iz will also be small for refraction at face AB a licuri lu = le = sini Sie we have is А There for for refraction at face AC sin da = urz Sinr, eir teira - ulritr2) - A 8 = (l=1) A le factors on which angle of daviation defends i) the angle of incidents (11) The angle of priom (1) the material of friom (iv) the ware length of light used. As a thin convex lens can be assumed to be made of prioma of small angles. So, both assertion and reason are correct and reason is the correct explanation of assertion. option A is correct answer.