Q no 7 explain in detail
Q.7. How many electrons constitute an electric current of 2 A. (Charge on an electron = 1.6 $\times {10}^{-19}$ C)
(A) 1.25 $\times {10}^{19}$
(B) 3.2 $\times {10}^{-19}$
(C) 1.25 $\times {10}^{18}$
(D) 3.21 $\times {10}^{-18}$

Dear student 

2A current means 2C charge transfer per second 

1 C charge =  6.25 x 10¹⁸ electrons 
so 2 C charge = 2x6.25x10¹⁸ electrons 
                       = 12.5x10¹⁸ electrons 
                       = 1.25 x 10 ¹⁹ electrons
So A is the correct answer .

Regards