# Class 10 Science TERM-2 SA -2

Summative Assignments
Question 1:
Draw ray diagrams to show the formation of a three times magnified (i) real image (ii) virtual image of an object kept in front of a converging lens. Mark the positions of object, F, 2F, O and position of image clearly in the diagram.
Question 2:
With respect to air the refractive index of kerosene is 1.44 and that of diamond is 2.42.
Calculate the refractive index of diamond with respect to kerosene
Question 3:
What is the far point and near point of the human eye with normal vision?
Question 4:
Refractive index of media P, Q, R and S are
P=> 1.22
Q => 1.51
R => 1.31
S => 1.71
Arrange the media in ascending order of the speed of light

Question 5:
A student finds the writing on the blackboard blurred and unclear when sitting on the last desk in the classroom. He however, sees it clearly when sitting on the front desk at an approximate distance of 2m from the blackboard. Draw ray diagrams to illustrate the formation of image of the blackboard writing by his eye-lens when he is seated at the (i) last desk (ii) front desk.
Name the kind of lens that would help him to see clearly even when he is seated at the last desk. Draw a ray diagram to illustrate how this lens helps him to see clearly.
Question 6:
Two lenses have power of (i) + 2D (ii) - 4D. What is the nature and focal length of each lens.?
Question 7:
An object is kept at a distance of 100cm from +2D len
Calculate the (i) image distance (ii) magnification in each of the two cases
Question 8:
Fossils provide evidences for organic evolution. a)What are fossils? b)What are the different methods for estimating the age of fossils?
Question 9:
Explain why?
(i) ‘Danger’ signal are red in color.
(ii) Convex mirrors are commonly used as rear – view mirrors.
Question 10:
a)What is the natural phenomenon behind the formation of a rainbow?
b)Name a device that can be used to observe such a phenomenon in the laboratory?
c)If you are facing a rainbow in the sky, what is the position of sun with respect to your position?