If the kinetic energy of a particle is increased to 16 times, the percentage change in the de Broglie wavelength of a particle is

In case of photoelectric emission from certain metal, the cutoff frequency is $\nu$. If the radiation of frequency $3\nu$ is incident on the metal plate, the maximum possible velocity of the emitted electrons will be ($m$ = mass of electron, $h$ = Planck's constant)

The triply ionized beryllium ($\text{Be}^{+++}$) has the same electron orbital radius as that of the ground state of hydrogen. Hence, the energy state of triply ionized beryllium is (Given $Z = 4$ for beryllium)

The angular momentum of the electron in the third Bohr orbit of a hydrogen atom is '$l$' so its angular momentum in the fourth Bohr orbit is