## Question

### Solution

Correct option is

n = 3

. For n = 1 state of hydrogen, we have E1 = C and for the nth state of Li++, we have

For E1 = En, we require  which gives n = 3.

#### SIMILAR QUESTIONS

Q1

A sample of a radioactive element has a mass of 10g at an instant t = 0. The oppropriate mass of this element in the element in the sample after two mean lives is

Q2

If the half lives of a radioactive element that decays in 6 days is 7/8. The fraction that decays in 10 days will be

Q3

The wavelength  of de Broglie waves associated with an electron (massm, charger e) accelerated through a potential difference of V is given by (his Planck’s constant)

Q4

A proton, when accelerated through a potential difference of V volts, has a wavelength  associated with it. If an alpha particle ius to have the same wavelength , it must be accelerated through a potential difference of

Q5

A proton and an electron move with the same velocity. The associated wavelength for proton is

Q6

Two particles of masses m and 2m have equal kinetic energies. Their de Broglie wavelength are in the ratio of

Q7

The wavelength of de Broglie wave associated with a thermal neutron of mass m at absolute temperature T is given by (here k is the Boltzmann constant)

Q8

The momentum of a photon of frequency v is

Q9

Which energy state of the triply ionized beryllium (Be+++) has the same electrons orbital radius as that of the ground state of hydrogen? Given Zfor beryllium = 4.

Q10

The total energy of the electron in the first excited state of hydrogen is –3.4 eV. What is the kinetic energy of the electron in this state?