The ratio for the speed of the electron in the 3^rd orbit of He⁺ to the speed of the electron in the 3^rd orbit of hydrogen atom will be :

The photodiode is used to detect the optical signals. These diodes are preferably operated in reverse biased mode because :

A signal of 100 THz frequency can be transmitted with maximum efficiency by :

The difference of speed of light in the two media A and B (v_A $$-$$ v_B) is 2.6 $$\times$$ 10⁷ m/s. If the refractive index of medium B is 1.47, then the ratio of refractive index of medium B to medium A is : (Given : speed of light in vacuum c = 3 $$\times$$ 10⁸ ms^$$-$$1)