102. Symbolic representation of four logic gate are shown below. Pick out which ones are for AND, NAND and NOT gates, respectively

 

38. A p−n photodiode is fabricated from a semiconductor with a band gap of 2.5eV. It can detect a signal of wavelength ?

37. Sodium has body centred packing. Distance between two nearest atoms is 3.7Â. The lattice parameter is ?

Three capacitors each of capacitance C and of breakdown voltage V are joined in series. The capacitance and breakdown voltage of the combination will be ?

Three concentric spherical shells have radii a, b and c (a < b < c) and have surface charge densities σ, −σ and σ respectively. If VA, VB and VC denotes the potentials of the three shells, then for c = a + b, we have ?

The electric potential at a point (x, y, z) is given by V = −(x^2)y − x(z^3) + 4. The electric field E at that point is ?

The mean free path of electrons in a metal is 4×10−8 m. The electric field which can give on an average 2eV energy to an electron in the metal will be in units of V/m ?