When monochromatic radiation of intensity $$I$$ falls on a metal surface, the number of photoelectrons and their maximum kinetic energy are N and T respectively. If the intensity of radiation is 2$$I$$, the number of emitted electrons and their maximum kinetic energy are respectively

The speed of light in media M₁ and M₂ are 1.5 $$ \times $$ 10⁸ m/s and 2.0 $$ \times $$ 10⁸ m/s respectively. A ray of light enters from medium M₁ to M₂ at an incidence angle i. If the rays suffers total internal reflection, the value of i is

The electron in the hydrogen atom jumps from excited state (n = 3) to its ground state (n = 1) and the photons thus emitted irradiate a photosensitive material. If the work function of the material is 5.1 eV, the stopping potential is estimated to be (the energy of the electron in n^th state E_n = $${{ - 13.6} \over {{n^2}}}eV$$)

The electric field of an electromagnetic wave in free space is given by $$\overrightarrow E = 10\cos ({10^7}t + kx)\widehat j\,\,V/m,$$ where t and x are in seconds and metres respectively. It can be inferred that
(1)  the wavelength $$\lambda $$ is 188.4 m.
(2)  the wave number k is 0.33 rad/m.
(3)  the wave amplitude is 10 V/m.
(4)  the wave is propagating along +x direction.

Which one of the following pairs of statements is correct ?