For an electron , if the uncertainty in velocity is v , the uncertainty in its position (x) is given by :
A radioactive sample is emitting 64 times radiations than non-hazardous limit .If its half-life is 2 hours , after what time it becomes non- hazardous ?
A metal surface is exposed to solar radiations :
the emitted electrons have energy less than a maximum value of energy depending upon frequency of incident radiations
the emitted electrons have energy less than maximum value of energy depending upon intensity of incident radiations
the emitted electrons have zero energy
the emitted electrons have energy equal to energy of photons of incident light
Which of the following transitions have minimum wavelengths ?
E = or E
Thus a decrease in wave length represents an increase in energy For n4 n1 transition .These are greater the. energy difference and lesser will be wavelength .Thus , for n4 n1 transition has minimum wavelength .
Orbital is :
circular path around the nucleus in which the electrons revolves
space around the nucleus where the probability of finding the electron is maximum
amplitude of electron wave
none of the above
Which of the following sequence is correct as per Aufbau principle ?
3s < 3d < 4s < 4p
ls < 2p < 4s < 3d
2s < 5s < 4p < 5d
2s < 5s < 4p < 5f
Ionic compounds are formed most easily with :
low electron affinity , high ionisation energy
high electron affinity , low ionisation energy
low electron affinity , low ionisation energy
high electron affinity , high ionisation energy
The enthalpy change (H) for the neutralisation of M HCl by caustic potash in dilute solution at 298 K is :