[rosierm]

Ok i have two questions and not sure how to get to the answer as the mark scheme doesn't give you working out:

first one:
A 10 mF capacitor is charged to 10v and then discharged completely through a small motor. During this process, the motor lifts a weight of mass o.10kg. If 10% of the energy stored in the capacitor is used to lift the weight, through what approx height will the weight be lifted?
a) 0.05 m
B) 0.10m
C) 0.50m
D) 1.00m
Answer: B

Second one:
A 1.0 microF capacitor is charge by means of a constant current of 10 MicroA for 20s. What is the energy finally stored in the capacitor?
the answer is 2.0 * 10^ -2 J

Thanks for any help

[soup]

1)Calculate the energy discharged by capacitor (E = 1/2 CV^2). Find 10% of that and then use E = mgh to calculate height. The energy discharged is being converted into gravitational potential energy.

2)Q = It. E = 1/2 Q^2/C .

[Little Ant]

May be a bit late to the party here but I'm pretty sure that the first of the two questions is A?