Q. Which of the following is incorrect ?
a. A convex mirror can give a virtual image.
b. A convex mirror cannot give a real image.
c. A concave mirror can give a virtual image.
d. A concave mirror can give a diminished virtual image.
A metal gives two chlorides ‘A’ and ‘B’. ‘A’ gives black precipitate with NH4OH and ‘B’ gives white precipitate .With KI ,‘B’ gives a red precipitate soluble in excess of KI. ‘A’ and ‘B’ are respectively :