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.

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.

Page swapping or page replacements are called page cannibalizing.

‘Unless’ is used to denote the condition i.e. ‘If’...... ‘Not’. So, again the use of negative word ‘not’ is superfluous. So, the phrase, ‘are not very’ needs to be replaced with ‘are very’ to make the sentence grammatically correct. Thus, the correct formation would be, ‘Unless, you are very careful, you will run into debt’.

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.

The molecules responsible for membrane transport are proteins.