Kinetic theory and Oscillations

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Dear Student, Read question and answers

Smt.Deepthy Roy

HSST( Physics )

GHSS

Elakunnapuzha

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Q1. For an oscillating simple pendulum,the displacement variable is ...

Answer : θ (t)

Hint:   x  = A cos θ  , θ  =  ω t + ϕ

Q2. Which of the following is not true in the case of a damped oscillation ?

Answer : Total energy increases

Hint:   E(t)= k A 2  exp (- b t m)  .1/2

Q3. Find the value of force constant of a spring which suspends a body ,

of mass 2 kg, oscillates with an angular frequency of 10 rad/s

Answer : 200  N / m

Hint:    k = m ω2       

Q4.  Two simple harmonic motions represented by   y 1 = 5 sin [2 π t + π  /4]

and     y 2 = 2 sin[ 2 π t +  π /3 ]  The ratio of amplitudes is ...

Answer : 5 : 2

Hint:      y =  A  sin [ ω t + ϕ ] ,   where  A = amplitude



Q5.  The period of a simple pendulum at the center of the earth is...

Answer : Infinity

Hint:      At the centre of the earth      g = 0  ,    T  =  2 π  ( l/g) ½


Q6. A gas that satisfies the relation PV = µ RT ,

at all temperatures and pressures is known as ...

Answer : Ideal gas

Hint:     Ideal gas equation is          PV = µ RT

Q7. The ratio of specific heats ( ᵞ ) of a mono atomic gas is..

Answer : 5 / 3

Hint:     For monoatomic gas  degrees of freedom is 3 . 

C V  = 3RT /2    and    C P = 5RT /2       ,   ᵞ   =  C P / C V

Q8. The average kinetic energy of the molecule is proportional to ...

Answer : Absolute temperature


Hint:      mv2 /2  =3  kB T /2  or         KE  α   T 

Q9. In a dynamical equilibrium .....

a) Molecules collide each other ,  

b)  Molecules change their speeds during collision   , 

c) Only the average  properties are constant  ,

d ) All the above

Answer : All the above

Hint:      In dynamic equilibrium the gas is full of activity

Q10. At NPT the ratio of molecules in 1 cc of oxygen to that in 1 cc of hydrogen is ...

Answer :  1 : 1

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