These are a few of the harder questions from my homework that is due tomorrow. Please Help.(adsbygoogle = window.adsbygoogle || []).push({});

1. The problem statement, all variables and given/known data

A) How much energy is wasted when 35C of charge flows through a 120V toaster in 5 sec? How much power?

B) An electron gun fires electrons from rest and smashes them into a screen that is .33m away. The accelerating voltage that causes this is 2850V.

1. What is the kinetic energy?

2. What is the velocity right before impact

3. What is the magnitude and direction of the electric field accelerating the electron?

4. What is the force experienced by the accelerating electron?

5. how much time does in take for the electron to make this trip?

C) Two opposite charged students bring their fingers towards each other and a spark jumps between their fingers at 7 cm apart. What is the electric field in the region between their fingers when the spark occurs. What is the potential difference between the two students (in voltage)?

2. Relevant equations

V=ed

W=qed

P=IV

KE=1/2mv^2

3. The attempt at a solution

I am really confused with these questions.

For the first one I have 840Watts and 4200J for the toaster

I don't get the electron gun one.

The spark one is equally confusing, we were given that the Emax in air is 3*10^6J, but I do not know if this is needed for this question.

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

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: Need help on Electric Field Questions

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