A convex mirror is used as a driving mirror because I. its image is erect II. It has a large field of view…

Step 1: Analyze the question We need to decide which reasons explain why a convex (diverging) mirror is used as a driving (rear-view) mirror.

Step 2: Concept A convex mirror always forms an image that is:

• virtual, erect (upright) and diminished (smaller than the object)
• located behind the mirror, regardless of where the object is

Because the image is diminished, the mirror can show a wide area of the road behind the driver. This gives a large field of view.

Step 3: Check each statement

• I. Its image is erect. TRUE. The driver sees vehicles the right way up, not inverted.
• II. It has a large field of view. TRUE. The outward-curved surface spreads out the reflected rays, so a wide area is seen in a small mirror.
• III. It has a long focal length. FALSE. This is not a reason for using it. A convex mirror's focal length is virtual, and a long focal length is not what makes it suitable. A longer focal length would mean less curvature and a smaller field of view, so this works against the mirror's purpose.

So only statements I and II are correct.

Step 4: Answer

Tip: Remember the three features of a convex mirror image: virtual, erect, diminished. "Diminished" is what gives the wide field of view. When a question lists "long focal length" as a reason for a driving mirror, treat it as a distractor. Also note that option C in this question appears to have a typo ("IIII"), but it doesn't affect the answer.