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Medical
103 Views   |  

For the reaction:

X_{2}O_{4}\left ( l \right )\rightarrow 2XO_{2}(g)

\Delta U=2.1k \ cal, \Delta S=20 cal\ K^{-1}  at 300K

Hence \Delta G is :-

  • Option 1)

    2.7k cal

  • Option 2)

    -2.7 k cal

  • Option 3)

    9.3k cal

  • Option 4)

    -9.3k cal

 
  Molar heat capacity for isobaric process C(p) -   - wherein or     Given,  Also,  Given,  On putting the value of  and  in the equation, we get -    Option 1) 2.7k cal This option is incorrect. Option 2) -2.7 k cal This option is correct. Option 3) 9.3k cal This option is incorrect. Option 4) -9.3k cal This option is incorrect.
Medical
238 Views   |  

A thermodynamic system undergoes cyclic process ABCDA as shown in fig. the work done by the system in the cycle is:

  • Option 1)

    P_{o}V_{o}

  • Option 2)

    2P_{o}V_{o}

  • Option 3)

    \frac{P_{o}V_{o}}{2}

  • Option 4)

    Zero

 
Using Cyclic Process - A cyclic process consist of a number of changes that return the system back to its initial state.   - wherein in cyclic process    Work done in cyclic process = Area of the cycle In the upper half, cycle is anti-clockwise while in lower half it is clockwise. Hence, net work done is zero. Option 1) This option is incorrect Option 2) This option is incorrect Option...
Medical
83 Views   |  

A monoatomic gas at a pressure P, having a volume V expands isothermally to a volume 2 V, and then adiabatically to a volume 16 V. the final pressure of the gas is: 

take\:\:\left( \gamma= \frac{5}{3} \right ) 

  • Option 1)

    64 P

  • Option 2)

    32 P

  • Option 3)

    \frac{P}{64}

  • Option 4)

    16 P

 
As learnt in Equation of state -   - wherein On solving    For Isothermal expansion, For adiabatic expansion,   Option 1) 64 P This option is incorrect Option 2) 32 P This option is incorrect Option 3) This option is correct Option 4) 16 P This option is incorrect
Medical
510 Views   |  

A body of mass (4m) is lying in x-y plane at rest. It suddenly explodes into three pieces. Two pieces, each of mass (m) move perpendicular to each other with equal speeds (V). The total Kinetic energy generated due to explosion is

  • Option 1)

    mV^{2}

  • Option 2)

    \frac{3}{2} mV^{2}

  • Option 3)

    2 mV^{2}

  • Option 4)

    4 mV^{2}

 

seems logical .we assume that the 3rd part ie mass 2m goes in (-x-y) plane though the problem does not specify.How to explain that mass 2m does not move in Z direction?

Medical
147 Views   |  

Steam at 100o C is passed into 20 g of water at 10o C. When water acquires a temperature of 80o C, the mass of water present will be:

[Take specific heat of water = 1 cal g-1 oC -1 and latent heat of steam = 540 cal g-1]

  • Option 1)

    24 g

  • Option 2)

    31.5 g

  • Option 3)

    42.5 g

  • Option 4)

    22.5 g

 
As discussed in Specific Heat - Amount of heat(Q) required to raise the temperature of unit mass through 1oC. - wherein   Specific heat of water  Latent heat of steam  Heat gained by 20g of water to change its temperature from  to  According to principle of calorimetry   or  total mass of water =  Option 1) 24 g This solution is incorrect Option 2) 31.5 g This solution is incorrect Option...
Medical
92 Views   |  

Copper of fixed volume 'V' is drawn into wire of length 'l'. When this wire is subjected to a constant force'F', the extension produced in the wire is '\Delta l' . Which of the following graphs is a straight line?

 

  • Option 1)

    \Delta l \:versus\:\frac{1}{l}

  • Option 2)

    \Delta l \:versus\:l^{2}

  • Option 3)

    \Delta l \:versus\:\frac{1}{l^{2}}

  • Option 4)

    \Delta l \:versus\:l

 
As discussed in Young Modulus - Ratio of normal stress to longitudnal strain it denoted by Y - wherein F -  applied force A -  Area  -  Change in lenght l - original length           Option 1) This solution is incorrect Option 2) This solution is correct Option 3) This solution is incorrect Option 4) This solution is incorrect
Medical
248 Views   |  

A certain number of spherical drops of a liquid of radius 'r' coalesce to form a single drop of radius 'R' and volume 'V'. If 'T' is the surface tension of the liquid, then:

 

  • Option 1)

    energy =4VT \left( \frac{1}{r}- \frac{1}{R} \right )is\:\:released

  • Option 2)

    energy =3VT \left( \frac{1}{r}+ \frac{1}{R} \right )is\:\:absorbed

  • Option 3)

    energy =3VT \left( \frac{1}{r}- \frac{1}{R} \right )is\:\:released

  • Option 4)

    Energy is neither released nor absorbed.

 
As discussed Surface Energy - It is defined as the amount of work done in increasing the area of the liquid against surface tension. -    As surface area decreases so energy is released energy released =  Option 1) This solution is incorrect Option 2) This solution is incorrect Option 3) This solution is correct Option 4) Energy is neither released nor absorbed. This solution is incorrect
Medical
95 Views   |  

If the focal length of objective lens is increased then magnefying power of:

  • Option 1)

    microscope will increase but that of telescope decrease.

  • Option 2)

    microscope and telescope both will increase.

  • Option 3)

    microscope and telescope both will decrease.

  • Option 4)

    microscope will decrease but that of telescope increase.

 
  Compound Microscope -   - wherein is distance from objective. Distance from eyepiece. Maximum magnification     Astronomical Telescope -   - wherein = focal length of objective focal length of eyepiece    For microscope magnifying power  For telescope magnifying power   magnifying power of microscope decreases and that of telescope increases Option 1) microscope will increase but...
Medical
83 Views   |  

In the Young's double-slit experiment, the intensity of light at a point on the screen where the path difference is \lambda is K, (\lambda being the wave length of light used). The intensity at a point where the path difference is \frac{\lambda }{4}, will be:

  • Option 1)

    K

  • Option 2)

    \frac{K}{4}

  • Option 3)

    \frac{K}{2}

  • Option 4)

    Zero

 
  Resultant Intensity of two wave - - wherein Intencity of wave 1 Intencity of wave 2 Phase difference      at a point where path difference is  When path a difference is   phase difference = Option 1) This option is incorrect  Option 2) This option is incorrect  Option 3) This option is correct  Option 4) This option is incorrect 
Medical
102 Views   |  

A beam of light \lambda =600 nm from a distant source falls on a single slit 1 mm wide and the resulting diffraction pattern is observed on a screen 2 m away. The distance between first dark fringes on either side of the central bright fringe is:

  • Option 1)

    1.2 cm

  • Option 2)

    1.2 mm

  • Option 3)

    2.4 cm

  • Option 4)

    2.4 mm

 
As we learnt in Fraunhofer Diffraction -   - wherein Condition of nth minima. slit width angle of deviation    distance between first daic fringe on both side means width of central maxima  Option 1) 1.2 cm This is incorrect option  Option 2) 1.2 mm This is incorrect option  Option 3) 2.4 cm This is incorrect option  Option 4) 2.4 mm This is correct option 
Medical
110 Views   |  

The ratio of the accelerations for a solid sphere (mass 'm' and radius 'R') rolling down and incline of angle '\theta' without slipping and slipping down the incline without rolling is

  • Option 1)

    5:7

  • Option 2)

    2:3

  • Option 3)

    2:5

  • Option 4)

    7:5

 
As discussed in Rolling of a body on an inclined plane - - wherein K=Radius of gyration = Angle of inclination       Option 1) 5:7 This option is correct. Option 2) 2:3 This option is incorrect. Option 3) 2:5 This option is incorrect. Option 4) 7:5 This option is incorrect.
Medical
113 Views   |  

The oscillation of a body on a smooth horizontal surface is represented by the equation, 

X = A cos (\omega t)

where, X = displacement at time t

 \omega = frequency of oscillation

Which one of the following graphs shows correctly the variation of 'a' with 't'?

  • Option 1)

  • Option 2)

  • Option 3)

  • Option 4)

 
As discussed Composition of two SHM in perpendicular direction -     - wherein Resultant equation    a=A coswt v=-AwSinwt a= i.e the variation of a with and correctly shown by graph (3) Option 1) This option is incorrect  Option 2) This option is incorrect  Option 3) This option is correct  Option 4) This option is incorrect 
Medical
88 Views   |  

The number of possible natural oscillation of air column in a pipe closed at one end of length 85 cm whose frequencies lie below 1250 Hz are:

( velocity of sound = 340 ms-1)

  • Option 1)

    4

  • Option 2)

    5

  • Option 3)

    7

  • Option 4)

    6

 
As learnt  Closed organ pipe - A closed organ pipe is a cylindrical tube having an air colume with one end closed. - wherein Condition of constructive interference         f =  if    n = 0     f0 = 100 Hz      n = 1      f1 = 300 Hz      n = 2      f2 = 500 Hz      n = 3      f3 = 700 Hz      n = 4      f4 = 900 Hz      n = 5      f5 = 1100 Hz      n = 6      f6 = 1300 Hz Possible natural...
Medical
92 Views   |  

In the following reaction, the product (A)

 

  • Option 1)

  • Option 2)

  • Option 3)

  • Option 4)

 
Product As discussed in Coupling reaction of aromatic diazonium - Diazonium ions of aromatic amines also undergo coupling reaction with aromatic rings having a strong activating group to form diazo compounds. - wherein    Product formed is a diazo compound with yellow or orange colour.   Option 1) This option is incorrect. Option 2) This option is incorrect. Option 3) This option is...
Medical
112 Views   |  

A speeding motorcyclist sees traffic jam ahead of him. He slows down to 36 km/hour. He finds that traffic has eased and a car moving a head of him at 18 km/hour is honking at a frequency of 1392 Hz. If the speed of sound is 343 m/s, the frequency of the honk as heard by him will be:

  • Option 1)

    1332 Hz

  • Option 2)

    1372 Hz

  • Option 3)

    1412 Hz

  • Option 4)

    1464 Hz

 
As we discussed frequency of sound when source is moving away and observer is moving towards the source - - wherein Speed of sound Speed of observer speed of source Original frequency apparent frequency   According to doppler's effect   Option 1) 1332 Hz Incorrect Option 2) 1372 Hz Incorrect Option 3) 1412 Hz Correct Option 4) 1464 Hz Incorrect
Medical
108 Views   |  

(i) H_{2}O_{2}+O_{3}\rightarrow H_{2}O+2O_{2}

(ii) H_{2}O_{2}+Ag_{2}O\rightarrow 2Ag+H_{2}O+O_{2}

Role of hydrogen peroxide in the above reactions is respectively -

  • Option 1)

    Oxidizing in (i) and reducing in (ii)

  • Option 2)

    Reducing in (i) and oxidizing in (ii)

  • Option 3)

    Reducing in (i) and (ii)

  • Option 4)

    Oxidizing in (i) and (ii)

 
As learnt in Structure of H2O2 (Hydrogen Peroxide) - It is non planar molecule. - wherein    In (i), O3 is reduced to O2 and in (ii), Ag2O is reduced to Ag. Option 1) Oxidizing in (i) and reducing in (ii) This option is incorrect Option 2) Reducing in (i) and oxidizing in (ii) This option is incorrect Option 3) Reducing in (i) and (ii) This option is correct Option 4) Oxidizing in (i) and...
Medical
92 Views   |  

Which of the following organic compounds has same hybridization as its combustion product (CO_{2}) ?

  • Option 1)

    Ethane

  • Option 2)

    Ethyne

  • Option 3)

    Ethene

  • Option 4)

    Ethanol

 
  Combustion - Alkane on heating in presence of air or O2 are completely oxidised to CO2 and water with evolution of large amount of heat. - wherein     Hybridisation of  in      is  Hybridisation of  in      is  Hybridisation of  in      is   Hybridisation of  in      is   Option 1) Ethane This option is incorrect. Option 2) Ethyne This option is correct. Option 3) Ethene This option is...
Medical
274 Views   |  

The weight of silver (at wt.=108) displaced by a quantity of electricity which displaces 5600 mL of O2 at STP will be:

  • Option 1)

    5.4 g

  • Option 2)

    10.8 g

  • Option 3)

    54.9 g

  • Option 4)

    108.0 g

 
  Second law of electrolysis - The masses of different substances, liberated or dissolved by the electricity are proportional to their equivalent masses. -     According to faraday secornd law =  => Option 1) 5.4 g incorrect Option 2) 10.8 g incorrect Option 3) 54.9 g incorrect Option 4) 108.0 g correct
Medical
95 Views   |  

Be2+ is isoelectronic with which of the following ions? 

  • Option 1)

    H+

  • Option 2)

    Li+

  • Option 3)

    Na+

  • Option 4)

    Mg2+

 
As we learnt in  Isosteres - Molecules or polyatomic ions containing same number of atoms and the same total numbers of electron are called isosteres.Generally isosteres have identical lewis structure.       -    Electronic config of  Electronic config of    Be2+ is isoelectronic unit  Option 1) H+ Incorrect Option 2) Li+ Correct Option 3) Na+ Incorrect Option 4) Mg2+ Incorrect
Medical
512 Views   |  

Magnetic moment 2.83 BM is given by which of the following ions?
(At nos. Ti=22, Cr=24, Mn=25, Ni=28):-

  • Option 1)

    Ti^{3+}

  • Option 2)

    Ni^{2+}

  • Option 3)

    Cr^{3+}

  • Option 4)

    Mn^{2+}

 
As we learned in concept Calculation of spin only magnetic moment - where n = no. of unpaired electron  - wherein    magnetic movement,    => x(x + 2) = 8 => x = 2 Electronic confiq of                                     Clearly, no of unpaired is = 2 therefore, solution is 2 Option 1) incorrect Option 2) correct Option 3) incorrect Option 4) incorrect
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