Questions

A periscope is an optical instrument that uses a system of prisms, lenses, or mirrors to reflect images through a tube.

Light from a distant object strikes the top mirror and is then reflected at an angle of 90 degrees down the periscope tube. At the bottom of the periscope, the light strikes another mirror and is then reflected into the viewer’s eye.

Hence, A periscope works by the principle of Total internal reflection.

It is a scheme across the river Rihand near Pipri in Mirzapur district of Uttar Pradesh

Ten kids will get each one apple. The eleventh kid will get the apple with the bowl.

Modal ‘can’ needs to be replaced with ‘could’ to make the sentence grammatically correct.‘Could’ is used to express power and possibility in past tense. Thus, the correct formation would be, ‘I wish I could help you’.

The slot covers on a computer reduce the dust build up inside the computer. So the slot covers should be present in proper place.The missing covers can disrupt the airflow design of the case and cause overheating problems.

Let their edges be a and b. Then,

a3/b3 = 1/27 (or) (a/b)3 = (1/3)3 (or) (a/b) = (1/3).

\Ratio of their surface area = 6a2/6b2 = a2/b2 = (a/b)2 = 1/9, i.e. 1:9.