(adsbygoogle = window.adsbygoogle || []).push({}); having lots of trouble with a few problems that are due tonight...please help!!!

1. A 0.28F capacitor is desired. What area must the plates have if they are to be separated by 1.2mm air gap?

I used C=E0 (A/d) and I keep getting the same and wrong answer. What am I doing wrong?

2. What potential difference acting over a distance of 3.5cm would be needed to balance the downward force of gravity so that an electron would remain stationary? Assume the electric field is uniform.

I used V=mass of electron*gravity*0.035m/1.6*E-19, and that gave me the wrong answer. Help anyone.

3. A 9.4V battery is connected to a bulb whose resistance is 2.1ohms. How many electrons leave the battery per minute.

I used ohm's law I=9.4/2.1 to get the current 4.476C/s. Then I multiplied 4.476c/s*60s/1.6E-19 and got 1.68E-17 electrons/minute...and that answer was wrong...any help?

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Having lots of trouble with a few problems that are due tonight please help

**Physics Forums | Science Articles, Homework Help, Discussion**