a capacitor of capacitance c = 4 mc is discharged through a resistor of resistance r = 4 k. how long will it take for the capacitor to lose half its initial stored energy?

It depends on the subject for me. some exams are easier than others so i usually go through it and answer questions i know based on my general knowledge, then double check after. going through the lesson can a lot  because the exams can be  very lesson-specific, but sometimes they are ridiculously long so a lot of people don't take the time. i did find that, when i went through the lessons, i was making 100's on my exams vs strictly using + the internet and  i make 90's. 

One of the angles would be 70 degrees and the other one would be 90 degrees