A battery charger circuit is intended to deliver a desired current into a battery and then maintain a fixed "float voltage" when full charge is reached. For a small car battery, a reasonable scenario would be to deliver 5 A to the battery until it reaches 13.8 V and then to maintain the converter output at 13.8 V indefinitely. Required:
a. What duty ratio will be needed to deliver 5 A of current when the battery is at low charge and has a terminal voltage of 11.5 V?
b. What duty ratio will be needed when the battery voltage reaches 13.8 V?

The intensity of a polarized electromagnetic wave is 12 w/m^2. part a) what will be the intensity after passing through a polarizing filter whose axis makes the angle θ=0∘ with the plane of polarization? part b) what will be the intensity after passing through a polarizing filter whose axis makes the angle θ=30∘ with the plane of polarization? part c) what will be the intensity after passing through a polarizing filter whose axis makes the angle θ=45∘ with the plane of polarization? part d) what will be the intensity after passing through a polarizing filter whose axis makes the angle θ=60∘ with the plane of polarization? part e) what will be the intensity after passing through a polarizing filter whose axis makes the angle θ=90∘ with the plane of polarization?

What is the increase in density of a medium due to wave travel?

The frequency of the fundamental of the guitar string is 320 hz. at what speed v do waves move along that string?