Question

Assertion: If the angle between the two plane mirror is ${72}^o$ and the object is asymmetrically placed between the two mirrors, then 5 images of the object will be formed.
Reason: For a given system of mirrors the total number of images formed due to successive reflection is equal to either $\frac{{360}^o}{\theta }$ or $\frac{{360}^o}{\theta }-1$ accordingly as $\frac{{360}^o}{\theta }$ is odd or even respectively.

• A. If both Assertion 'and Reason are correct and Reason is the correct explanation of Assertion
• B. If both Assertion and Reason are correct, but Reason is not the correct explanation of Assertion
• C. If Assertion is correct but Reason is incorrect
• D. If Assertion is incorrect but Reason is correct

Answer 1

The correct option is A If both Assertion 'and Reason are correct and Reason is the correct explanation of Assertion

The number of image formed is either $n=\frac{{360}^o}{\theta }$ for n=odd or $n-1$ for n=even

Here, $\theta ={72}^o$

Hence, $n=\frac{{360}^o}{{72}^o}=5$ which is odd.

Hence, number of image formed=$5$

Hence, both assertion and reason are correct and reason is correct explanation of assertion.

Answer-(A)