What type of energy conversion takes place in a voltaic cell?

Define dew point. i am writing this part to be able to ask the question

What is the lowest number energy level where a d sublevel is found

Which of the following is an example of physical change not a chemical change? a) a log gives off heat and light as it burns. b) a tree stores energy from the sun in its fruit. c) a penny lost in the grass slowly changes color. d) a water pipe freezes and cracks on a cold night.