I want to know whether it is necessary to leave time between physical exercise and taking a bath. If necessary, then how many minutes? Also, is it advisable to exercise after eating?
It's not really necessary but it's definitely recommend. It's quite important to cool down after exercising. I can't tell you an exact time you should wait since you should know when you're cooled down. Usually, I wait around 15 - 20 minutes before taking a bath or taking a shower.
Exercising after eating? No, it's not advisable. If you're eating, your blood will be in your intestine and stomach to help you to digest. So you're missing important blood to keep up your mind and body. I think you know this feeling of being tired after eating a great - basically a huge - meal. Don't overdo it, exercising is no fun with a full belly.
I've found this searching the web. It also recommends you to cool down first before taking your bath or shower.