One mole of a monoatomic ideal gas undergoes four thermodynamic processes as shown schematically in the pV - diagram below. Among these four processes, one is isobaric, one is isochoric , one is isothermal and one is adiabatic. Match the processes mentioned in List -I with the corresponding statements in List -II



A) $P\rightarrow4;Q\rightarrow3;R\rightarrow1;S\rightarrow2$

B) $P\rightarrow1;Q\rightarrow3;R\rightarrow2;S\rightarrow4$

C) $P\rightarrow3;Q\rightarrow4;R\rightarrow1;S\rightarrow2$

D) $P\rightarrow3;Q\rightarrow4;R\rightarrow2;S\rightarrow1$


Consider a hydrogen -like ionised atom with atomic number Z , with  a single electron. In the emission spectrum  of atom, the photon emitted  in the n= 2 to n=1 transition has energy 74.8 eV higher than the photon emitted in the n=3 to n=2 transition.The ionisation energy of the hydrogen atom is 13.6 eV. The value of Z is..........

A) 3

B) 6

C) 4

D) 2


In a photoelectric experiment , a parallel beam of monochromatic light with power of 200 W is incident on a perfectly absorbing cathode of work function 6.25 eV  . The frequency of light is just above the threshold frequency, so that the photoelectrons are emitted with negligible kinetic energy.  Assume that the photoelectron emission  efficiency is 100% . A potential difference of 500 V  is applied between the cathode and the anode. All the emitted electrons are incident normally on the anode and are absorbed. The anode experiences a force F= n × 10-4 N due to the impact of the eletrons The value of n is .................(Take mass of the electron, m=9× 10-31 kg and eV = 1.6 × 10-19 J)

A) 26

B) 24

C) 42

D) 12


One mole of monoatomic ideal gas undergoes an adiabatic expansion in which its volume becomes eight times its initial value. If the initial temperature of the gas is 100K and the universal gas constant  R= 8.0 j mol-1 K-1 , the decrease in its internal energy in joule, is ..............

A) 450 J

B) 900 J

C) 850 J

D) 750 J


A steel wire of diameter 0.5 mm and Young's modulus 2 × 1011 N m-2   carries a load of mass m.  The length of the wire with the load is 1.0 m. A  vernier scale with 10 divisions is attached to the end of this wire. Next to the steel wire is reference wire to which a main scale, of least count 1.0 mm , is attached. The 10 divisions of the vernier scale correspond to 9 divisions of the main scale. Initially , the zero of vernier scale coincides with the zero  of main scale . If the load on the steel wire is increased by 1.2 kg, the vernier scale division which concides with a main scale division is ...........   Take , g= 10 m s-1 and π =3.2)

A) 3rd Division

B) 5th Division

C) 6th Division

D) 9th Division