Some reactions of $NO _2$ relevant to photochemical smog formation are
Identify $A , B , X$ and $Y$
A block of certain mass is placed on a rough floor. The coefficients of static and kinetic friction between the block and the floor are 0.4 and 0.25 respectively. A constant horizontal force \( F = 20 \, \text{N} \) acts on it so that the velocity of the block varies with time according to the following graph. The mass of the block is nearly (Take \( g = 10 \, \text{m/s}^2 \)):
There is a number of factors that contribute to the pollution of the environment. Some of the major causes of atmospheric pollution are given below -