Question

Which of the following forms a virtual and erect image for all positions of the object?
A. Convex lens.
B. Plane mirror.
C. Convex mirror.
D. Concave mirror

Answer 1

An image of an object is formed by a mirror if the two reflected rays of the object by the same mirror coincide or meet. Similarly the image of an object is formed by a lens if the two refracted rays of the object by the lens will meet at a point. If the two refracted or reflected rays actually meet then the image formed is real and if the two rays are diverse after refraction or reflection then they will never meet and if we extend them backward then the rays will seem to meet. This meeting point is called a virtual image. If the image is straight as the object then the image is erect and if the image is on the other side and seems to be inverted then the image is inverted.

Complete step-by-step answer:
Consider option A. A convex lens will form different kinds of image depending upon the position of the object. A converging lens and a converging lens can form a real image so a convex lens will not form a virtual and erect image for all positions of the object. So option A is not the correct option.
Now moving to option B. An image formed by a plane mirror will be virtual and erect for all positions of the object. So option B is correct. It is shown in the picture below.

A convex mirror is a diverging lens and will produce a virtual and erect image for all positions of the object so option C. is correct. It is shown in the diagram below.

A concave mirror will produce virtual as well as real image depending upon the position of the object so it will not produce virtual and erect image for all positions of the object. So option D is not the correct option.

So, the correct answer is “Option B and C”.

Note: The image formed by a plane mirror is virtual, erect and the same size as that of the object. And at the opposite site of the mirror. The image formed by a convex mirror is always virtually erect and diminished. So the convex mirror is used as rear view mirrors to capture more field of view.