A stream of electrons from a heated filament was passed between two charged plates kept at a potential difference V esu. If e and m are charge and mass of an electron, respectively, then the value of h/λ (where λ is wavelength associated with electron wave) is given by:

• 2meV

• 
• 

• mev

C.

The relation between h/λ and energy is given as:
Applying de-Broglie wavelength and kinetic energy term in eV.
de-Broglie wavelength for an electron (λ) = h/p
⇒ p  = h/ λ       (i)
Kinetic energy of an electron = eV
As we know that,

From equations (i) and (ii), we get

The heats of combustion of carbon and carbon monoxide are −393.5 and −283.5 kJ mol−1, respectively. The heat of formation (in kJ) of carbon monoxide per mole is:

• 676.5

• -676.5

• -110.5

• 110 s

The species in which the N atom is in a state of sp hybridization is:

• NO₂^-

• NO₃^-

• NO₂
  

• NO₂⁺

D.

NO₂⁺

The equilibrium constant at 298 K for a reaction A+B ⇌ C+D is 100. If the initial concentration of all the four species were 1 M each, then equilibrium concentration of D (in mol L⁻¹ ) will be:

• 0.818

• 1.818

• 1.182

• 0.182

B.

1.818

Which of the following atoms has the highest first ionisation energy?

• Na

• K

• Sc

• Rb