Kinetic Theory Of Gases : Physics Entrance Exam

 

Q.1.  If k is the Boltzmann constant , the average kinetic energy of a gas molecule at absolute temperature T is 

A) k T/2

B) 3 k T/4

C) k T

D) 3 k T/2

Q.2. At room temperature (27C ) the rms speed of the molecules of a certain diatomic gas is found to be 1920 ms.The  gas is 

A) H

B) F

C) O

D) CI 

Explanation-

We know that  which gives 

 Since  M = 2 , the gas is hydrogen .

Q.3.  If a g as has f degrees of freedom, the ratio  of the gas is 

A) 

B) 

C) 

D)  

Explanation-

We know that  = no . of degress of freedom x molar gas constant / 2 or 

Q.4.  Two ideal gases at absolute temperature T and T are mixed . There is no loss of energy in this process . If n and n are the respective number of molecules of the gases , the temperature of the mixture will be 

A) 

B) 

C) 

D)  

Explanation-

Q.5.  Four molecules of a gas have speeds 1,2,3 and 4 km  . The value of the root mean square speed of the gas molecule is 

A)  

B) 

C) 

D)  

Explanation-

The rms speed = 

Q.6.   The average kinetic energy of a molecule of a gas at absolute temperature T is proportional to 

A) 1/T

B) 

C) T

D) T 

Explanation-

The average kinetic energy of a molecule of a gas at absolute temperature T is given by .

Q.7.  The root mean square speed of the molecules of a gas at absolute temperature T is proportional to 

A) 1/T

B) 

C) T

D) T 

Explanation-

The root mean square speed of the molecules of a gas is given by .

Q.8.    and  respectively represent the average kinetic energy of a molecule of oxygen and hydrogen. If the two gases are at the same temperature , which of the following statements is true ?

A)   >  

B)   =  

C)   <  

D)  Nothing can be said about the magnitude of   and  as the information given is insufficient  

Explanation-

The average kinetic energy of molecule =  kT which is independent of the molecular mass .

Q.9.  The temperature of an ideal gas is increased from 120 K to 480 K. If at 120 K , the root mean square speed of the gas molecules is v , then at 480 K it will be 

A) 4 v

B) 2 v

C) 

D)  

Explanation-

 . 

Q.10.  A vessel contains 1 mole of O gas ( molar mass 32 ) at a temperature T . The pressure of the gas is P . An identical vessel containing one mole of He gas ( molar mass 4 ) at a temperature  2 T has a pressure of 

A) 

B) P

C) 2 P

D) 8 P

Explanation-

For a gas , PV = nRT . Hence 

                   ( P ) 

 

Plant Physiology: Biology Entrance

                  

        click here (For More Questions based on Biology )

Q.1.  Root hairs do not play a role in 

A) water uptake 

B) oxygen uptake 

C) carbon dioxide uptake 

D) mineral uptake 

Q.2.  Decreased rate of photosynthesis at high concentration  of oxygen is referred to as 

A) Pasteur effect

B) Emerson effect

C) Warburg effect

D) Richmond - Lang effect 

Q.3.  Which of the following is not part of the transpiration cohesion - adhesion theory of the ascent of xylem sap ? 

A) The evaporation of water from the mesophyll cells , which initiates a pull of water molecules from neighboring cells and eventually from the tracheid's 

B) The transfer of this pull from one water molecule to the next due to the cohesion caused by hydrogen bonds 

C) The hydrophilic walls of the narrow tracheid's and vessels that help to maintain the column of water against the force of gravity 

D) The use of proton pumps to create membrane potentials that facilitate the accumulation of mineral ions 

Q.4.  The productivity of crop begins to decline when the leaves begin to wilt mainly because 

A) flaccid mesophyll cells are incapable of photosynthesis 

B) stomata close , preventing CO from entering the leaf 

C) photolysis , the water splitting step of photosynthesis , cannot occur when there is a water deficiency 

D) accumulation of CO in the leaf inhibits enzymes required from photosynthesis 

Q.5.  The ion involved in stomata movement is 

A) Zn

B) Mg

C) Mn

D) K 

Q.6.  Which of the following is a correct statement about nitrogen fixation ?

A) Plants convert atmospheric nitrogen to ammonia 

B) Ammonia is converted to nitrates , which is the part of nitrogen most easily absorbed by plants 

C) Mutant strains of Rhizobium are able to secrete excess nitrogen into the soil 

D) Enzyme nitrogenase reduces N to from ammonia 

Q.7.  Which of the following is a correct statement about nitrogen fixation ?

A) Plants convert atmospheric nitrogen to ammonia 

B) Ammonia is converted to nitrates , which is the part of nitrogen most easily absorbed by plants 

C) Mutant strains of Rhizobium are able to secrete excess nitrogen into the soil 

D) Enzyme nitrogenase reduces N to from ammonia 

Q.8.  The principal cation in alkaline soil is 

A) Na

B) K

C) Ca 

D) H 

Q.9.  Sulphur is an important nutrient for optimum growth and productivity in 

A) Pulse crops 

B) Cereals 

C) Fiber crops 

D) Oilseed crops 

Q.10.  Which of the following nutrients is incorrectly paired with its function in a plant ?

A) Calcium - formation of cell walls , combines with pectin to glue cells together 

B) Magnesium - constituent of chlorophyll , cofactor for important enzymes 

C) Iron - component of chlorophyll 

D) Potassium - important in osmotic regulations , cofactor