Which of the following reagents reacts with benzaldehyde to produce $1$-phenylethanol?

An electron collides with an atom in its ground state at rest. The atom then emits a photon of energy $E_{photon}$. In this process,the change $\Delta E_{elec}$ in the electron's energy is

On heating,which of the following releases $CO_2$ most easily?

The natural frequency of an $L-C$ circuit is $1,25,000 \text{ cycles/s}$. Then the capacitor $C$ is replaced by another capacitor with a dielectric medium of dielectric constant $K$. In this case,the frequency decreases by $25 \text{ kHz}$. The value of $K$ is

The most significant value of vegetative propagation is that:

$A$ particle is performing $SHM$ starting from the extreme position. The graphical representation shows that, between displacement and acceleration, there is a phase difference of: