Atoms

If an alpha particle with energy 7.7 MeV is bombarded on a thin gold foil, the closest distance from nucleus it can reach is m. (Atomic number of gold = 79 and 14 0 = 9 109 in SI units)

1. 2.95 10-16
2. 3.85 10-14
3. 2.95 10-14
4. 3.85 10-16

The energy of an electron in an orbit of the Bohr's atom is -0.04E0 eV where E0 is the ground state energy. If L is the angular momentum of the electron in this orbit and h is the Planck's constant, then 2 Lh is :

1. 6
2. 2
3. 5
4. 4

In a hydrogen like ion, the energy difference between the 2nd excitation energy state and ground is 108.8 eV. The atomic number of the ion is:

1. 1
2. 4
3. 3
4. 2

For a hydrogen atom, the ratio of the largest wavelength of Lyman series to that of the Balmer series is

1. 5 : 27
2. 27 : 5
3. 3 : 4
4. 5 : 36

Considering the Bohr model of hydrogen-like atoms, the ratio of the radius of 5th orbit of the electron in Li2+ and He+ is

1. 32
2. 23
3. 49
4. 94

Given below are two statements : In the light of the above statements, choose the most appropriate answer from the options given below :

1. Both Statement I and Statement II are correct
2. Statement I is correct but Statement II is incorrect
3. Both Statement I and Statement II are incorrect
4. Statement I is incorrect but Statement II is correct

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R. In the light of the above statements, choose the correct answer from the options given below

1. A is true but R is false
2. Both A and R are true and R is the correct explanation of A
3. A is false but R is true
4. Both A and R are true but R is NOT the correct explanation of A

An electron in the hydrogen atom initially in the fourth excited state makes a transition to nth energy state by emitting a photon of energy 2.86 eV. The integer value of n will be .

Considering Bohr's atomic model for hydrogen atom : Choose the correct answer from the options given below :

1. (A), (B) only
2. (A), (D) only
3. (A), (C) only
4. (B), (D) only

Assuming the validity of Bohr's atomic model for hydrogen-like ions the radius of Li++ ion in its ground state is given by 1Xa0, where X = (Where a0 is the first Bohr's radius.)

1. 2
2. 9
3. 1
4. 3