Radiation of wavelength $$\lambda ,$$ is incident on a photocell. The fastest emitted electron has speed $$v.$$ If the wavelength is changed to $${{3\lambda } \over 4},$$ the speed of the fastest emitted electron will be:

Identify the semiconductor devices whose characteristics are given below, in the order $$(a), (b), (c), (d)$$ :

If $$a, b, c, d$$ are inputs to a gate and $$x$$ is its output, then, as per the following time graph, the gate is :

In an experiment for determination of refractive index of glass of a prism by $$i - \delta ,$$ plot it was found thata ray incident at angle $${35^ \circ }$$, suffers a deviation of $${40^ \circ }$$ and that it emerges at angle $${79^ \circ }.$$ In that case which of the following is closest to the maximum possible value of the refractive index?