NCERT Class X Science Class: Chapter –10. Light – Reflection and Refraction – Part-7

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Long Answer Questions

Question 30:

Draw ray diagrams showing the image formation by a concave mirror when an object is placed

(a) Between pole and focus of the mirror

(b) Between focus and center of curvature of the mirror

(c) At center of curvature of the mirror

(d) a little beyond center of curvature of the mirror

(e) At infinity

Answer:

(a) Image formation by a concave mirror when an object is placed between pole and focus of the mirror:

Object at COC of mirror a

Object at COC of Mirror A

Object at COC of mirror a

(b) Image formation by a concave mirror when an object is placed between focus and center of curvature of the mirror:

Object at COC of mirror d

Object at COC of Mirror D

Object at COC of mirror d

(c) Image formation by a concave mirror when an object is placed at center of curvature of the mirror:

Object at COC of mirror c

Object at COC of Mirror C

Object at COC of mirror c

(d) Image formation by a concave mirror when an object is placed a little beyond center of curvature of the mirror:

Object at COC of mirror

Object at COC of Mirror

Object at COC of mirror

(e) Image formation by a concave mirror when an object is placed at infinity:

Concave Mirror

Concave Mirror

Concave Mirror

Question 31:

Draw ray diagrams showing the image formation by a convex lens when an object is placed

(a) When the Object is placed between and O

(b) When the Object is placed at

(c) When the Object is placed between

(d) When an object is placed at infinity

(e) When the Object is placed beyond

Answer:

(a) Image formation by a convex lens when an object is placed when the Object is Placed between and O:

Image formation by a convex lens a

Image Formation by a Convex Lens A

Image formation by a convex lens a

(b) Image formation by a convex lens when an object is placed when the Object is Placed at :

Image formation by a convex lens

Image Formation by a Convex Lens

Image formation by a convex lens

(c) Image formation by a convex lens when an object is placed when the Object is Placed between :

Covex Lens

Covex Lens

Covex Lens

(d) Image formation by a convex lens when an object is placed at infinity:

Image formation bobject is placed at infinity

Image Formation Bobject is Placed at Infinity

Image formation bobject is placed at infinity

(e) Image formation by a convex lens when the Object is Placed beyond :

Image formation Object is Placed beyond 2F 1

Image Formation Object is Placed Beyond 2F 1

Image formation Object is Placed beyond 2F 1

Question 32:

Write laws of refraction. Explain the same with the help of ray diagram, when a ray of light passes through a rectangular glass slab.

Answer:

The following are the laws of refraction of light

(i) The incident ray, the refracted ray and the normal to the interface of two transparent media at the point of incidence, all lie in the same plane.

Image refracted of light

Image Refracted of Light

Image refracted of light

(ii) The ratio of sine of angle of incidence to the sine of angle of refraction is constant, for the light of a given colour and for the given pair of media. This law is also known as Snell’s law of refraction. And the constant is called refractive index. The ray diagram is as shown.

Image Snell's law of refraction

Image Snell's Law of Refraction

Image Snell's law of refraction

In a rectangular or glass slab, the emergent rays are parallel to the incident ray because the extant of bending of the ray of light at the opposite parallel faced of rectangular glass slab are equal and opposite, so that emergent ray is parallel to incident ray

Question 33:

Draw ray diagrams showing the image formation by a concave lens when an object is placed

(a) When the Object is at Infinity

(b) When the Object is Placed between O and F

(c) When the Object is Placed at any Position between O and Infinity

Answer:

(a) Image formation by a concave lens when an object is placed when the object is at Infinity:

Image formation by a concave at Infinity

Image Formation by a Concave at Infinity

Image formation by a concave at Infinity

(b) Image formation by a concave lens when an object is placed when the object is Placed between O and F:

Image formation by a concave at O and F

Image Formation by a Concave at O and F

Image formation by a concave at O and F

(c) Image formation by a concave lens when an object is placed when the object is Placed at any position between O and Infinity:

Image formation by a concave O and Infinity

Image Formation by a Concave O and Infinity

Image formation by a concave O and Infinity

Question 34:

Draw ray diagrams showing the image formation by a convex mirror when an object is placed

(a) At infinity

(b) At finite distance from the mirror

Answer:

(a) Convex mirror when an object is placed at infinity:

Image convex mirror infinity

Image Convex Mirror Infinity

Image convex mirror infinity

(b) Convex mirror when an object is placed at finite distance from the mirror:

Covex Mirror

Covex Mirror

Covex Mirror