Related Questions

The correct relation between theoretical oxygen demand (TOD), Biochemical oxygen demand (BOD) and Chemical oxygen demand (COD) is given by
A TOD > BOD > COD
B TOD > COD > BOD
C BOD > COD > TOD
D COD > BOD > TOD
A,B,C,D,E,G and I are seven friends who study in three different standards namely 5th, 6th and 7th such that not less than two friends study in the same standard. Each friend also has a different favorite subject namely History, Civics, English, Bangla, Science , Maths , and Economics but not necessarily in the same order. A likes Maths and studies in the 5th standard with only one other friend who likes Bangla. I studies with tow other friends . Both the friends who study with I like languages (Here languages include only Science , English and Bangla ) . D studies in the 6th standard with only one person and does not like Civics . E studies with only one friend . The one who likes history does not study in 5th or 6th standard . E does not like languages. C does not like English , Science or Civics. Which combination represents E's favorite subject and the standard in which he studies?
A Civics and 7th
B Economics and 5th
C Civics and 6th
D History and 7th
One molecule of oxygen consists of __________ atoms of oxygen.
A 2
B 4
C 8
D 16
The relative stability of a sewage sample, whose dissolved oxygen is same as the total oxygen required to satisfy BOD, is
A 1
B 100
C Infinite
D Zero
Oxygen is separated by distillation from air after its liquefaction. The boiling point of oxygen is about __________ °C.
A -83
B -183
C -196
D -218
The ratio of oxygen available to the oxygen required for stabilisation of sewage is called the
A Bacterial stability factor
B Relative stability
C Biological oxygen demand (BOD)
D Oxygen ion concentration
একটি অক্সিজেন সিলিন্ডারের আয়তন 10 x 105 cm3 এবং এতে 300 বায়ুমন্ডলীয় চাপে অক্সিজেন ভর্তি আছে। কিছুটা ব্যবহারের পর দেখা গেল যে, চাপ 200 বায়ুমন্ডলীয় চাপে নেমে গেছে। ব্যবহারকৃত অক্সিজেনের আয়তন কত?(The volume of an oxygen cylinder is 10 x 105 cm3 and pressure is 300 atm. After some use, the pressure drops to 200 atm. What is the volume of the used oxygen?)
A 1000 L
B 500 L
C 2000 L
D 1200 L
E 1500 L
Fresh grapes contain 90% water by weight while dried grapes contain 20% water by weight. What is the weight of dry grapes available from 20 kg of fresh grapes?
A 2 kg
B 2.4 kg
C 2.5 kg
D None of these
Vegetable oils contain large quantity of glycerides of unsaturated acids. When the vegetable oils contain high amount of saturated fatty acids, it is termed as __________ oil.
A Drying
B Semi-drying
C Non-drying
D None of these
Fresh grapes contain 80 percent water while dry grapes contain 10 percent water. If the weight of the dry grapes is 250 kg what is total weight when it was fresh? 
A 1000 kg
B 1100 kg
C 1125 kg
D 1225 kg

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