Assertion (A) Phenols give o-and p-nitrophenol on nitration with conc. $H N O_{3} a n d H_{2} S O_{4}$ mixture.
Reason (R) - OH group in phenol is o-,p-directing.
(a) Assertion and reason both are correct and reason is correct explanation of assertion.
(b) Assertion and reason both are wrong statements.
(c) Assertion is correct statement but reason is wrong statement.
(d) Assertion is wrong statement but reason is correct statement.
(e) Both assertion and reason are correct statements but reason is not correct explanation of assertion.

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Assertion :If a convex lens of focal length 40 cm is put in contact with a concave lens of 25 cm, then the power of the combination is - 1.5D. Reason: P=P1+P2=1f1+1f2

The correct option is A Both Assertion and Reason are correct and Reason is the correct explanation for AssertionWhen a convex lens is put in contact with a concave lens we have,P=P1+P2Also P=1f⟹P=1f1+1f2Given f1=0.4m and f2=−0.25m⟹P=−1.5D

Assertion :If a convex lens of focal length 40 cm is put in contact with a concave lens of 25 cm, then the power of the combination is - $1.5 D$ . Reason: $P = P_{1} + P_{2} = \frac{1}{f_{1}} + \frac{1}{f_{2}}$