Question Papers and Doubts
- Food chains are very important for the survival of most species. 1. b) 100 J 2. c) Third Trophic level 3 a) Act at every trophic level of the food chain 4. c) Energy is unidirectional and matter is repeate... 1
- A biogas plant is where biogas is produced by fermenting biomass. 1. b) B 2. b) its non-renewable 3. (b) Waste water feed → digester → biogas → biogas storage → generator 4. (c) (iii) and (iv) 5. (d) presen... 1
- The primary reason behind the formation of the toxic foam is high phosphate content in the wastewater because of deterge 1. a) 10-11 2. (b) high concentration of hydroxide ion (OH⁻) and low concentration of hydronium ion (H₃O⁺) 3. (c) S<Q<R<P 4. (a) decreased l... 1
- For an internal combustion engine to move a vehicle down the road, it must convert the energy stored in the fuel into 1 - (d) 2 - (c) Oxidation & Exothermic reaction 3 - (a) 4 - (a) Limited supply of air leads to incomplete combustion of fuel 5 - (b) Nitroge... 1
- The reaction between MnO2 with HCl is depicted in the following diagram. It was observed that a gas with bleaching 1(c) redox reaction 2(a) dry Ca(OH)_(2 ) 3(a)MnO₂ is getting reduced whereas HCl is getting oxidized 4(b) Basic oxide 5(b) Reaction will not... 1
- Marble’s popularity began in ancient Rome and Greece, where white and off-white marble were used to construct a variety 1. Calcined gypsum 2. 0-5 min 3. photosynthesis 4. polluted water is acidic in nature hence it reacts with calcium carbonate 5. calcium oxid... 1
- Which term of ap is first negative 50,45,40........ 12th term a+(n-1)d \\ = 50+(12-1)(-5) \\ = 50+(-55) =-5 2