Class 7 Science Chapter 11 MCQ

Concave mirror and convex lens can only from enlarge image of an object. As convex mirror and concave lens always from a diminished image of an object.

The image formed by a plane mirror is at the same distance behind the mirror as the object is in front of it. Therefore, the distance between object and image is given by distance between object and mirror + distance between mirror and image. = 0.5 m + 0.5 m = 1 m

When an object is placed at a distance between focal length and twice the focal length of a concave mirror, then the image formed by concave mirror is real, inverted and larger than object. When an object is placed close to concave mirror (at less than focal length), the image formed by a concave mirror is virtual, erect and larger than the object.

We know that a convex lens gives a magnified image of a closed object. Used in this way, a convex lens is commonly known as a magnifying glass. A magnifying glass is a convex lens which is used to make small things look bigger by producing their magnified images. In other words, to use a convex lens as a magnifying glass, the object should be at a less distance than the focal length of convex lens. Convex lenses are used as magnifying glasses and convex lens also used in making spectacles, cameras, microscope, telescope and binoculars etc.

Remember, that whether an object is placed at a large distance or it is close to convex mirror, a convex mirror always forms an image which is virtual, erect and smaller than the object. Changing the position of object in front of a convex mirror only changes the size of image. But in every case, the image remains smaller than the object. (Note: A plane mirror and a convex mirror always forms a virtual and erect image of an object.)

Here, all the statements are correct. Hence your answer will be option [D].

The objects having polished, shining surfaces reflect more light than objects having unpolished dull surfaces.

We can see the objects around us because they reflect light received from a non-luminous object. We can see a table lying in a room because it reflects light falling on it in all the directions.

Here, all the statements are correct. Hence your answer will be option [D].

Here, all the statements are correct. Hence your answer will be option [D].

Here, all the statements are incorrect. Hence your answer will be option [D].

We know that convex lens is used as magnifying glass in microscope, telescope etc. Convex lens is also used in spectacles to correct far sightedness. Concave lens is used in spectacles to correct short sightedness.

Here, all the statements are correct. Hence your answer will be option [D].

True, the image formed by a concave mirror shows lateral inversion, i.e., left seems to be right and right seems to be left.

As only a concave mirror can form a real image. Plane mirror and convex mirror always form a virtual image of an object.

As in case of plane mirror, image formed is virtual, erect and of same size and in case of convex mirror, image is virtual, erect and smaller in size.

A rainbow can only be seen in the sky when the sun is behind you in rainy season.

Here, all the statements are correct. Hence your answer will be option [D].

A concave mirror is also known as a “Converging mirror”. When the rays of light come closer after reflection, we say that the rays of light are converging. Generally, the concave mirror reflects the parallel rays of light in such a way that after reflection all the rays converge or meet at one point called “focus” in front of the mirror.

A shining steel spoon represents both, a concave mirror as well as convex mirror. The front side of a spoon is bent inward so the front side of a shining spoon represents a concave mirror. The backside of a spoon is bulging outward, so the backside of a shining spoon represents a convex mirror.

Here, all the statements are correct. Hence your answer will be option [D].

An object is placed at a large distance or it is close to the concave lens, a concave lens always forms an image which is virtual, erect and smaller than the object. Changing the position of object in front of a concave lens only changes the size of image. But in every case, the image formed by concave lens remains smaller than the object. Since, a concave lens always forms a smaller image than the object. Therefore, object always look smaller when seen through a concave lens.

Whether an object is placed at a large distance or it is close to convex mirror, a convex mirror always forms an image which is virtual, erect and smaller than the object. The outer surface or back side of a shining steel spoons acts like a convex mirror. So, if you look into the outer side or back side of a shining steel spoon, we will see a virtual, erect in smaller image of our face. Only this happens due to bulging out structure of convex mirror.

Suppose, a beam of parallel rays of light falls on a convex mirror from the left side. We will see that after reflection from convex mirror, the parallel rays of light are spreading out. We can say that a beam of parallel light-rays diverges or spreads out after reflection from a convex mirror. Therefore, a convex mirror is known as a diverging mirror. Similarly, in the case of concave lens, when a beam of parallel rays of light falls on a concave lens from the left side. We will see that after passing through the concave lens the rays of light are diverging or spreading out. Thus, a concave lens is a diverging lens. In this respect, a concave lens is similar to a convex mirror because they diverge the light rays.

A concave lens can only from virtual, erect and diminished image of an object. As virtual and erect image formed by a convex lens is always magnified.