In the following electrical circuit, the reading in the milliammeter is
(Take knee voltage of silicon diode $= 0.7$ V)

The material used for solar cell should have band gap
(A) equal to zero.
(B) equal to $0.08$ eV.
(C) between $1.0$ eV to $1.8$ eV.
(D) equal to $2$ eV.

For a two input logic gate, when the inputs are 'zero' and 'zero' the output is 'one'. When the inputs are 'one' and 'zero' the output is 'zero'. The type of logic gate is

In n-type semiconductor
A) pentavalent impurity are dopants and holes are majority carriers.
B) trivalent impurity are dopants and electrons are minority carriers.
C) pentavalent impurity are dopants and electrons are majority carriers.
D) trivalent impurity are dopants and holes are majority carriers.