Physics, asked by Riya1always1, 1 year ago

Sunita takes a mirror which is depressed at the centre and mounts it on a mirror stand.An erect and enlarged image of her face is formed.She places the mirror on a stand along a meter scale at 15 cm mark.In front of this mirror, she mounts a white screen and moves it back and forth along the meter scale till a sharp, well-defined inverted image of a distant tree is formed on the screen at 35 cm mark.(i) Name the mirror and find its focal length.(ii) Why does Sunita get sharp image of the distant building at 35 cm mark?

Answers

Answered by svsriharsha

(i) concave mirror and focal length is 20 cm.

(ii) because screen is kept at focal point as image of distant object forms at focus.

svsriharsha: since she observed image of distant tree on the screen kept at 35 cm. mirror is placed at 15 cm. so image distance is 35 - 15 = 20 cm. since she formed image of distant object, image forms at focal point. i hope this helps you.

svsriharsha: if any doubt or any mistake regarding answer let me know.

Riya1always1: OK

svsriharsha: thank u

sarohakaran79: Can you please explain me how you find the answer . Please please

svsriharsha: hi

svsriharsha: we know that when light rays coming from infinite then image forms at focal point. so mirror is at 15 cm and screen placed at 35 cm. so when object at distant image forms at focal point means image distance is same as focal point. so 35 - 15 = 20 cm.

svsriharsha: so image distance means distance between image and mirror.

svsriharsha: so here image of distant tree means light is from infinite distance.

svsriharsha: any doubt u can ask

Answered by BendingReality

Answer:

( i )

Sunita used concave mirror.

Focal length of mirror is :

= > 35 cm - 15 cm

= > 20 cm .

( ii )

As we know concave mirror always form image at focus when object is placed at infinity. Hence image is form sharp image at it was placed at 35 cm .

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