An old man took his two grandchildren to a park. on reaching the park, the children went to play. the old man took four rounds of the park, then sat down to read a newspaper. he read it with the of his spectacle. after sometime, he realised that he had left the children for a long time. he looked around but could not see the children with the spectacle he was wearing. he realised that he had forgotten his other spectacle which he used to see faraway places. he called out their names but his sound did not reach the children playing little away. finally, with the of some people near him he was able to reach the children. a) name the defect of eye the grandfather was suffering from?

The defect of eye that the grandfather was suffering from was presbyopia.

Explanation:

The grandfather uses a spectacle to read newspaper which makes us think that he has hyperopia which is a condition in which a person can see distant objects but has a problem focusing on objects that are up close. But as the grandfather try to find his grandchildren, we observe that he can not see farther objects as well. This means that the grandfather do not have hyperopia but the defect his eyes has is called presbyopia.

A person cannot have both myopia and hyperopia at the same time because they are related to the shortening or lengthening of the eyeball but a person with presbyopia will have problem focusing on farther or nearby objects.

Myopia:

In myopia, the eyeball is too long for the normal focusing power of the eye. As a result, images of distant objects appear blurred. Also called Shortsightedness.

Hyperopia:

In hyperopia, the eyeball is too short for the normal focusing power of the eye. Nearby objects appear blurred. Also called Farsightedness.

Presbyopia:

Presbyopia is a decreased elasticity of the lens due to advancing age. A person with this defect cannot see nearby objects and as well as far objects clearly.

work: w = fd (given)

work done by chet   =50*1 = 50 j

work done by mika =40*2 = 80 j

work done by sara =30*1.5 = 45 j

work done by bill =60*0.5 = 30 j

students in order from the greatest amount of work done to the least is mika> chet> sara> bill

hence option (b) is correct.

causes

fossil fuels burn

cities become more industrialized

human population grows worldwide