1.
A converging mirror is used i which of the following:-
Correct Answer
A. Solar furnaces
Explanation
A converging mirror is used in solar furnaces because it is designed to focus sunlight onto a small area, creating intense heat. This concentrated heat can be used for various purposes such as generating electricity or melting metals. The mirror's shape allows it to converge the incoming parallel rays of sunlight to a single focal point, maximizing the concentration of energy.
2.
Mirror used by dentist to get larger view of teeth is a concave mirror.
Correct Answer
A. True
Explanation
A concave mirror is used by dentists to get a larger view of teeth because it converges the light rays and forms a magnified image. This allows the dentist to see the teeth more clearly and examine them in detail.
3.
Which of the following in use in magnifying glass:-
Correct Answer
D. Convex lens
Explanation
A convex lens is used in a magnifying glass because it is thicker in the middle and thinner at the edges. This shape causes light rays to converge, or come together, which creates a magnified image. The convex lens bends the light rays inward, allowing the object being viewed to appear larger and clearer.
4.
What can we say about the medium in which light bends towards the normal while travelling from one medium to another?
Correct Answer
B. We can say that, first is a rarer medium and second is a denser medium
Explanation
When light travels from one medium to another and bends towards the normal, it indicates that the first medium is less optically dense (rarer) compared to the second medium, which is more optically dense (denser). The bending of light towards the normal occurs due to the change in the speed of light as it passes from one medium to another.
5.
Which mirror can produce a virtual, erect and magnified image of an object?
Correct Answer
A. Concave mirror
Explanation
A concave mirror can produce a virtual, erect, and magnified image of an object. This is because a concave mirror is curved inward, causing light rays to converge at a focal point. When an object is placed beyond the focal point, a magnified and upright virtual image is formed.
6.
The angle of incidence for a ray of light having zero reflection angle is
Correct Answer
A. 0
Explanation
When the reflection angle is zero, it means that the ray of light is incident perpendicular to the surface. In this case, the angle of incidence is also zero because it is the angle between the incident ray and the normal to the surface. So, when there is no reflection angle, the angle of incidence is 0 degrees.
7.
If an incident ray passes through the focus, the reflected ray will
Correct Answer
B. Be parallel to the principal axis
Explanation
When an incident ray passes through the focus of a concave mirror, it will be reflected parallel to the principal axis. This is because the focus is a special point on the principal axis where all incident rays that are parallel to the principal axis converge after reflection. Therefore, when an incident ray passes through the focus, it will be reflected back along the same path as if it were parallel to the principal axis.
8.
Magnifying power of a concave lens is
Correct Answer
B. Always < 1
Explanation
A concave lens is a diverging lens, meaning it disperses light rays. When light rays pass through a concave lens, they diverge and do not converge to a point. This causes the image formed by the lens to be smaller and farther away than the object. The magnifying power of a lens is determined by the ratio of the image distance to the object distance. Since the image formed by a concave lens is smaller than the object, the magnifying power is always less than 1.
9.
If the magnification produced by a lens has a negative value, the image will be
Correct Answer
D. Virtual and erect
Explanation
If the magnification produced by a lens has a negative value, it means that the image formed by the lens will be virtual and erect. A negative magnification indicates that the image is formed on the same side as the object, and it will be upright (erect) compared to the object. Additionally, a virtual image is formed when the light rays do not actually converge at the image position, but they appear to diverge from a virtual position.
10.
When the object is placed between f and 2f of a convex lens, the image formed is
Correct Answer
C. Beyond 2f
Explanation
When an object is placed between the focal point (f) and twice the focal length (2f) of a convex lens, the image formed is located beyond 2f. This is because in this position, the image is virtual, upright, and magnified. The lens converges the light rays from the object and forms an image on the opposite side of the lens. Since the object is placed closer to the lens than the focal point, the image is formed on the same side as the object but beyond 2f.