COMEDK 2025 Morning Shift | Atoms and Nuclei Question 1 | Physics

According to Bohr's theory of hydrogen atom, the speed of the electron, its energy and radius of its orbit vary with the principal quantum number $n$, respectively as

$\frac{1}{n}, n^2, \frac{1}{n^2}$

$\frac{1}{n}, \frac{1}{n^2}, n^2$

$n, \frac{1}{n^2}, n^2$

$\frac{1}{n^2}, \frac{1}{n}, n^2$

COMEDK 2025 Morning Shift

MCQ (Single Correct Answer)

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Which, of the following is true of the Balmer series of the hydrogen spectrum?

a. The series is in the visible region.

b. The entire series falls in the ultraviolet region

c. The entire series falls in the infrared region

d. The series is partly in the visible region and partly in the infrared region

COMEDK 2025 Morning Shift

MCQ (Single Correct Answer)

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In a nuclear fusion reaction, two nuclei, $A$ and $B$ fuse to produce a nucleus $C$, releasing an amount of energy $\Delta \mathrm{E}$ in the process. If the mass defects of the three nuclei are $\Delta M_A, \Delta M_B$ and $\Delta M_C$ respectively, then which of the following relations is true? ( $c$ is the speed of light).

$\Delta M_A+\Delta M_B=\Delta M_C+\frac{\Delta E}{c^2}$

$\Delta M_A-\Delta M_B=\Delta M_C+\frac{\Delta E}{c^2}$

$\Delta M_A-\Delta M_B=\Delta M_C-\frac{\Delta E}{c^2}$

$\Delta M_A+\Delta M_B=\Delta M_C-\frac{\Delta E}{c^2}$

COMEDK 2024 Evening Shift

MCQ (Single Correct Answer)

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The binding energy per nucleon for $$\mathrm{C}^{12}$$ is $$7.68 \mathrm{~MeV}$$ and that for $$\mathrm{C}^{13}$$ is $$7.47 \mathrm{~MeV}$$. The energy required to remove a neutron from $$\mathrm{C}^{13}$$ is

$$7.92 \times 10^{-13} \mathrm{~MeV}$$

$$4.95 \times 10^{-13} \mathrm{eV}$$

$$7.92 \times 10^{-13} \mathrm{~J}$$

$$7.92 \times 10^{-19} \mathrm{~J}$$

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