Consider two hypothetical nuclei \( X_1 \) and \( X_2 \) undergoing \( \beta \) decay, resulting in nuclei \( Y_1 \) and \( Y_2 \), respectively. The decay scheme and the corresponding \( J^P \) values of the nuclei are given in the figure. Which of the following option(s) is/are correct? (\( J \) is the total angular momentum and \( P \) is parity)
1. Fermi transition:
A Fermi transition occurs when the total angular momentum \( J \) and parity \( P \) of the nucleus do not change during the decay. This type of transition happens when \( \Delta J = 0 \) and \( \Delta P = 0 \), meaning the spin and parity are preserved in the decay.
2. Gamow-Teller transition:
A Gamow-Teller transition involves a change in the total angular momentum (\( \Delta J \neq 0 \)), but the parity remains unchanged (\( \Delta P = 0 \)).
3. Analyzing the given system:
In the first decay \( X_1 \to Y_1 \), both the initial and final nuclear states have the same parity (\( P = 0^+ \) to \( P = 0^+ \)), and there is no change in the total angular momentum (\( J = 0 \to J = 0 \)), indicating a Fermi transition.
In the second decay \( X_2 \to Y_2 \), the initial state is \( J^P = 0^+ \) and the final state is \( J^P = 1^+ \), indicating a change in the total angular momentum (\( \Delta J = 1 \)) while the parity remains unchanged (\( P = 0^+ \) to \( P = 1^+ \)), which is characteristic of a Gamow-Teller transition.
Thus, the correct answer is (B).
The figure shows an opamp circuit with a 5.1 V Zener diode in the feedback loop. The opamp runs from \( \pm 15 \, {V} \) supplies. If a \( +1 \, {V} \) signal is applied at the input, the output voltage (rounded off to one decimal place) is:
A wheel of mass \( 4M \) and radius \( R \) is made of a thin uniform distribution of mass \( 3M \) at the rim and a point mass \( M \) at the center. The spokes of the wheel are massless. The center of mass of the wheel is connected to a horizontal massless rod of length \( 2R \), with one end fixed at \( O \), as shown in the figure. The wheel rolls without slipping on horizontal ground with angular speed \( \Omega \). If \( \vec{L} \) is the total angular momentum of the wheel about \( O \), then the magnitude \( \left| \frac{d\vec{L}}{dt} \right| = N(MR^2 \Omega^2) \). The value of \( N \) (in integer) is: