The oscillating magnetic field in a plane electromagnetic wave is given by
$$B_{y}=5 \times 10^{-6} \sin 1000 \pi\left(5 x-4 \times 10^{8} t\right) T$$. The amplitude of electric field will be :
Light travels in two media $$M_{1}$$ and $$M_{2}$$ with speeds $$1.5 \times 10^{8} \mathrm{~ms}^{-1}$$ and $$2.0 \times 10^{8} \mathrm{~ms}^{-1}$$ respectively. The critical angle between them is :
A body is projected vertically upwards from the surface of earth with a velocity equal to one third of escape velocity. The maximum height attained by the body will be :
(Take radius of earth $$=6400 \mathrm{~km}$$ and $$\mathrm{g}=10 \mathrm{~ms}^{-2}$$ )
The maximum and minimum voltage of an amplitude modulated signal are $$60 \mathrm{~V}$$ and $$20 \mathrm{~V}$$ respectively. The percentage modulation index will be :