The path difference between two identical light waves at a point $$Q$$ on the screen is $$3 \mu \mathrm{m}$$. If wavelength of the waves is $$5000 \mathop A\limits^o$$, then at point $$Q$$ there is

If the maximum efficiency of a full wave rectifier is $$x \%$$ and that of half-wave rectifier is $$y \%$$, then the relation between $$x$$ and $$y$$ is

Two bodies $$A$$ and $$B$$ start from the same point at the same instant and move along a straight line. body $$A$$ moves with uniform acceleration $$a$$ and body $$B$$ moves with uniform velocity $$v$$. They meet after time $$t$$. The value of $$t$$ is

A small steel ball is dropped from a height of $$1.5 \mathrm{~m}$$ into a glycerine jar. The ball reaches the bottom of the jar $$1.5 \mathrm{~s}$$ after it was dropped. If the retardation is $$2.66 \mathrm{~m} / \mathrm{s}^2$$, the height of the glycerine in the jar is about (acceleration due to gravity $$g=9.8 \mathrm{~m} / \mathrm{s}^2$$ )