Recent content by langenase

Homework Statement I'm trying to find the focal length of the diverging lens. The converging lens is 24cm behind a diverging lens. The focal length of the converging lens is 31cm. I know that parallel light strikes the diverging lens and then affter passing through the converging lens the...

Homework Statement I'm supposed to estimate at what temp. copper will have the same resistivity as tungsten at 20 deg. C. Homework Equations The only equation I think is relevant is p=p0[1+alpha(T-T0)] The Attempt at a Solution I know the resistivity of both copper and...

I'm a little confused about what to set E equal to. The voltage due to a point charge is when r is infinity is 0. But how does that relate to the electric field?

The field outside the sphere is given by the equation E=k(Q/r^2) I solved for Q and got units in C*m. Was it wrong for me to set E=500V?

Homework Statement A 32 cm diameter conducting sphere is charged to 500 V relative to V=0 and r = infinity. (a) What is the surface charge density sigma? (b) At what distance will the potential due to the sphere be only 10 V? Homework Equations The Attempt at a Solution I...