In which of the two following cases would you recommend winnowing ? Case 1 : when lighter part of the mixture is useful and the husk is unwanted
Case 2 : when lighter part of the mixture is unwanted and the husk is useful

As we know that, Winnowing is used when the lighter particles is required to remove. Hence, in Case 2 the lighter part is removed and the remaining is needed.

electrical potential energy =0.072 j

explanation:

electrical potential energy is given by

u= q δv

q= charge=6 c

δv= potential difference and is given by

δv= e d

e= electric field

d= distance=5 mm=0.005 m

δv=2.4 (0.005)=0.012 v

now electric potential energy= u= q δv

u=6 (0.012)

u=0.072 j