IIT-JEE 2008 Paper 1 Offline | Atoms and Nuclei Question 46 | Physics

1

IIT-JEE 2008 Paper 1 Offline

MCQ (Single Correct Answer)

+3

-1

In a mixture of H - He$$^+$$ gas (He$$^+$$ is singly ionized He atom), H atoms and He$$^+$$ ions are excited to their respective first excited states. Subsequently, H atoms transfer their total excitation energy to He$$^+$$ ions (by collisions). Assume that the Bohr model of atom is exactly valid.

The quantum number n of the state finally populated in He$$^+$$ ions is :

A

2

B

3

C

4

D

5

2

IIT-JEE 2008 Paper 1 Offline

MCQ (Single Correct Answer)

+3

-1

In a mixture of H - He$$^+$$ gas (He$$^+$$ is singly ionized He atom), H atoms and He$$^+$$ ions are excited to their respective first excited states. Subsequently, H atoms transfer their total excitation energy to He$$^+$$ ions (by collisions). Assume that the Bohr model of atom is exactly valid.

The wavelength of light emitted in the visible region by He$$^+$$ ions after collisions with H atoms is

A

$$6.5\times10^{-7}$$ m

B

$$5.6\times10^{-7}$$ m

C

$$4.8\times10^{-7}$$ m

D

$$4.0\times10^{-7}$$ m

3

IIT-JEE 2008 Paper 1 Offline

MCQ (Single Correct Answer)

+3

-1

In a mixture of H - He$$^+$$ gas (He$$^+$$ is singly ionized He atom), H atoms and He$$^+$$ ions are excited to their respective first excited states. Subsequently, H atoms transfer their total excitation energy to He$$^+$$ ions (by collisions). Assume that the Bohr model of atom is exactly valid.

The ratio of the kinetic energy of the $$n=2$$ electron for the H atom to that of He$$^+$$ ion is

A

$$\frac{1}{4}$$

B

$$\frac{1}{2}$$

C

1

D

2

4

IIT-JEE 2007 Paper 2 Offline

MCQ (Single Correct Answer)

+3

-1

Electrons with de-Broglie wavelength $$\lambda$$ fall on the target in an X-ray tube. The cut-off wavelength of the emitted X-rays is

A

$$\lambda_{0}=\frac{2 m c \lambda^{2}}{h}$$

B

$$\lambda_{0}=\frac{2 h}{m c}$$

C

$$\lambda_{0}=\frac{2 m^{2} c^{2} \lambda^{3}}{h^{2}}$$

D

$$\lambda_{0}=\lambda$$