### NEET Physics - New - Atoms and Nuclei

#### Question - 1

The ratio of wavelengths of the last line of Balmer series and the last line of Lyman series is:

• A 1
• B 4
• C 0.5
• D 2

#### Question - 2

If an electron in a hydrogen atom jumps from the 3rd orbit to the 2nd orbit, it emits a photon of wavelength $\lambda$. When it jumps from the 4th orbit to the 3rd orbit, the corresponding wavelength of the photon will be :

• A (16/25)$\lambda$
• B (9/16)$\lambda$
• C (20/7)$\lambda$
• D (20/13)$\lambda$

#### Question - 3

Consider 3rd orbit of He+ (Helium) using nonrelativistic approach, the speed of electron in this orbit will be :

• A 0.73 x 106 m/s
• B 3.0 x 108 m/s
• C 2.92 x 106 m/s
• D 1.46 x 106 m/s

#### Question - 4

Ratio of longest wave lengths corresponding to Lyman and Balmer series in hydrogen spectrum is:

• A 5/27
• B 3/23
• C 7/29
• D 9/3

#### Question - 5

A proton carrying 1 MeV kinetic energy is moving in a circular path of radius R in uniform magnetic field. What should be the energy of an a-particle to describe a circle of same radius in the same field?

• A 1 MeV
• B 0.5 MeV
• C 4 MeV
• D 2 MeV

#### Question - 6

Radioactive material 'N has decay constant '8$\lambda$' and material 'B' has decay constant '$\lambda$'. Initially they have same number of nuclei. After what time, the ratio of number of nuclei of material 'B' to that 'N will be 1/e?

• A 1/7$\lambda$
• B 1/8$\lambda$
• C 1/9$\lambda$
• D 1/$\lambda$

#### Question - 7

The wavelength of the first line of Lyman series for hydrogen atom is equal to that of the second line of Balmer series for hydrogen like ion. The atomic number Z of hydrogen like ion is :

• A 4
• B 1
• C 2
• D 3

#### Question - 8

The energy of a hydrogen atom in the ground state is - 13.6 eV. The energy of He+ ion in the first excited state will be :

• A -13.6 eV
• B - 27.2 eV
• C - 54.4 eV
• D - 6.8 eV

#### Question - 9

An alpha nucleus of energy 1/2mv2 bombards a heavy nuclear target of charge Ze. Then the distance of closest approach for the alpha nucleus will be proportional to :

• A 1/Ze
• B ${ \nu }^{ 2 }$
• C 1/m
• D 1/${ \nu }^{ 2 }$

#### Question - 10

A source S1 is producing, 1015 photons per second of wavelength 5000 $\mathring { A }$. Another source 52 is producing 1.02 x 1015 photons per second of wavelength 5100$\mathring { A }$. Then, (power of S2)/(power of S1) is equal to :

• A 1.00
• B 1.02
• C 1.04
• D 0.98