JEE Main 2025 (Online) 24th January Evening Shift | Atoms and Nuclei Question 4 | Physics

JEE Main 2025 (Online) 24th January Evening Shift

MCQ (Single Correct Answer)

-1

The energy E and momentum p of a moving body of mass m are related by some equation. Given that c represents the speed of light, identify the correct equation

$\mathrm{E}^2=\mathrm{pc}^2+\mathrm{m}^2 \mathrm{c}^4$

$\mathrm{E}^2=\mathrm{pc}^2+\mathrm{m}^2 \mathrm{c}^2$

$\mathrm{E}^2=\mathrm{p}^2 \mathrm{c}^2+\mathrm{m}^2 \mathrm{c}^4$

$\mathrm{E}^2=\mathrm{p}^2 \mathrm{c}^2+\mathrm{m}^2 \mathrm{c}^2$

JEE Main 2025 (Online) 24th January Morning Shift

MCQ (Single Correct Answer)

-1

During the transition of electron from state A to state C of a Bohr atom, the wavelength of emitted radiation is $2000 \mathop A\limits^o$ and it becomes $6000 \mathop A\limits^o$ when the electron jumps from state B to state C. Then the wavelength of the radiation emitted during the transition of electrons from state A to state B is

$4000 \mathop A\limits^o$

$6000 \mathop A\limits^o$

$2000 \mathop A\limits^o$

$3000 \mathop A\limits^o$

JEE Main 2025 (Online) 23rd January Evening Shift

MCQ (Single Correct Answer)

-1

Given below are two statements. One is labelled as Assertion (A) and the other is labelled as Reason (R).

Assertion (A) : The binding energy per nucleon is found to be practically independent of the atomic number A , for nuclei with mass numbers between 30 and 170 .

Reason (R) : Nuclear force is long range. In the light of the above statements, choose the correct answer from the options given below :

(A) is true but (R) is false

Both (A) and (R) are true and (R) is the correct explanation of (A)

(A) is false but (R) is true

Both (A) and (R) are true but (R) is NOT the correct explanation of (A)

JEE Main 2025 (Online) 23rd January Morning Shift

MCQ (Single Correct Answer)

-1

A radioactive nucleus $\mathrm{n}_2$ has 3 times the decay constant as compared to the decay constant of another radioactive nucleus $n_1$. If initial number of both nuclei are the same, what is the ratio of number of nuclei of $n_2$ to the number of nuclei of $n_1$, after one half-life of $n_1$ ?

1/4

1/8

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