Assertion (A) : Convex mirrors are used as rearview-mirrors in vehicles.

Reason (R1): They form erect and enlarged image.

Reason (R2) : They have wider field of view.

The correct answer is: (A) is true and only (R2) is correct explanation for (A).

Step-by-Step Explanation:

1. Evaluating Assertion (A):
Assertion (A) states that convex mirrors are used as rear-view mirrors in vehicles. This statement is true. Drivers rely on rear-view mirrors to see the traffic behind them to ensure safe driving.

2. Evaluating Reason (R1):
Reason (R1) states that convex mirrors form erect and enlarged images. This statement is false. While a convex mirror always forms an erect (upright) and virtual image of an object, the image formed is always diminished (smaller than the object), not enlarged.

3. Evaluating Reason (R2):
Reason (R2) states that convex mirrors have a wider field of view. This statement is true. Because convex mirrors curve outwards, they diverge light rays and cover a significantly larger area compared to flat (plane) mirrors or concave mirrors. This allows the driver to view a much wider expanse of the road behind them.

Conclusion:
Assertion (A) is correct, Reason (R1) is incorrect because the image is diminished rather than enlarged, and Reason (R2) correctly explains why convex mirrors are chosen for rear-view purposes. Therefore, (A) is true and only (R2) is the correct explanation for (A).