You have completed your design of a new surgical headlamp. you have decided to power the headlamp using four aa rechargeable batteries. each battery is rated at 1.2v, 2550 mah. your design uses an led light that consumes a constant 3w. the led is driven by a current source that takes power from the batteries and provides a constant current to the led. the current source is 95% efficient. how long will the led run before the batteries are depleted?

More solar radiation is absorbed by earth’s surface than by

For the car in the picture ,in which direction is the normal force? -into the screen -down -out of the screen -up

In the future, people will only enjoy one sport: electrodisc. in this sport, you gain points when you cause metallic discs hovering on a field to exchange charge. you are an electrodisc player playing the popular four disc variant. the disks have charges of qa = −8.0 µc, qb = −2.0 µc, qc = +5.0 µc, and qd = +12.0 µc. (1) you bring two disks together and then separate them. you measure the resulting charge of these two disks and find that it is +5.0 µc per disk. which two disks did you bring together? (a) a and b (b) a and c (c)a and d (d)b and c(e) b and d (f) c and d. (2) you bring three disks together and then separate them. you measure the resulting charge of these three disks and find that it is +3.0 µc per disk. which three disks did you bring together? a, b, and c (a) a, b, and d (c) a, c, and d (d) b, c, and d. (3) given the resulting charge of each disk measured in (b) is +3.0 µc, how many electrons would you need to add to a disk of this charge to electrically neutralize it? electrons