Answer: A) Acid rain Explanation: Secondary pollutants include ozone, which is formed when hydrocarbons (HC) and nitrogen oxides (NOx) combine in the presence of sunlight.   Whereas Primary pollutant are those pollutants that are directly emitted from their sources, like CO2, CO, SO2 as these gases are directly emitted form burning of fossil fuels.   Acid rain, which is formed when sulfur dioxide or nitrogen oxides react with water, sulfuric acid etc.   Hence, Acidrain is a secondary air pollutant.

A Paper.

Answer: B) Rs. 441 Explanation: Given principal amount = Rs. 8000 Time = 3yrs Rate = 5% C.I for 3 yrs = 8000 x 105100 x 105100 x 105100 - 8000= Rs. 1261   Now, C.I for 2 yrs = 8000 x 105100 x 105100= Rs. 820    Hence, the required difference in C.I is 1261 - 820 = Rs. 441

Answer: C) Tea Explanation: Makaibari is the world's first tea factory and was established in 1859 in Darjeeling, West Bengal.    It is most expensive tea in India which costs around 1.12 lakhs for 1 kg of tea.   Hence, Makaibari is the costliest variety of Tea.

A Secret.

SHORT is the required five letter word, which becomes SHORTER when two letters 'ER' are added to it.

Answer: A) Glass Explanation: Because the refractive index of glass is highest, light travels slowly in Glass.  We know that the speed of light depends on the refraction index. The higher the index of refraction is, the slower the speed of light is. R.I of air and vacuum = 0 (air is a teeny bit more but can be taken as 0) R.I of water = 1.33 R.I of glass = 1.4.   Hence, Light travels slowest in Glass.

Answer: B) 2 : 1 Explanation: Given that train K crosses a pole in 30 seconds and train L crosses the same pole in one minute and 15 seconds. Let the length of train K be Lk and that of train L be Ll given that Lk = 3/4 Ll As the train K and L crosses the pole in 30 seconds and 80 seconds respectively, => Speed of train K = sk = Lk/30 Speed of train L = sl = Ll/80 Lk = 3/4 Ll => sk = 3/4 Ll/(30) = Ll/40 Ratio of their speeds = sk : sl = Ll/40 : Ll/80 => 1/40 : 1/80  =  2 : 1