Objective-EM and Entropy

CSIR JRF/NET Physical Science

Atomic , Molecular Physics and more…..Test 20

1         If a current carrying conductor is placed in mag field, the force of the conductor is calculated bya)Cross product *                                                b) dot product

c)simple product                                                              d) None of the above

2         The direction of force of a current carrying conductor in a mag field is given by

a)      Cork screw rule                                                         b)Lenz’s law

c)Fleming’s  Left hand rule*                                                d)  Fleming’s  Right hand rul

  If m be the magnetic dipole moment of a current loop, then the torque τ can be written as

a)      τ =m.B                          b) τ =mxB*                         c) τ =0                   d) τ =m/B           

4       The relation .=0 is based on

a)continuity equation                                                    b) Faraday’s law                              

c) Gauss law*                                                                    d) Ohm’s law

5       Clausius inequality in thermodynamic is

a)        ≤0*                     b) ≥0                           c)  >0            d)  <0

6        The change in entropy in an isobaric process iis

a) 2.303 mc_plog T₂/T₁*                                                    b)2.303 mlog T₂/T₁                          

c) 2.303 mc_vlog T₁/T₂                                                       d) 2.303 RTlog T₂/T₁        

7        Change in entropy when 2 kg  ice at zero degree C is converted into steam at 100 degree C is

a)18200J/K                          b) 120J/K                             c) 27150J/K         d) 17150J/K*

8         Change in entropy when 1kg water at 100 degree C is converted into steam at the same temperature is---J/K

a)      2000                               b) 6000*                                               c) 7000                  d) 8000

9        The change in entropy when 50g of water at 15 degreeC is mixed with 80g of water at 40 degreeC is---J/K

a) 10.9                                   b)9.10                                   c) 0.47*                                d) 1.47 

1     Change in entropy when100g of water at 20 degree C is mixed with 120g of water at 50 degree C and the mixture is then heated to 100 degree C is

a)173.9J/K*                        b) 140J/K                             c) 508J/K                              d) 109 J/K