Open-Response Homework Problem 1.1 Since 1982, a penny has contained 2.5grams of copper. The atomic weight of copper is 63.546g/mole and the atomic number is 29. How many electrons are in a penny? Open-Response Homework Problem 1.2 A solid, insulating sphere has a radius of 15cm.

(a)If it carries a uniform surface charge density of a = -0.5pC/m2, calculate the total charge of the sphere.

(b)if it carries a uniform volume charge density of p = 250nC/m3, calculate the total charge of the sphere.

Optional Questions

The questions in this section will not be graded. You may work them if you feel you need additional practice.

Open-Response Homework Problem 1.3 This problem asks you to calculate the charge densities of the proton and the atom.

(a)A hydrogen atom has a radius of about r = 1 x 10-1°m. Modelling the charge of the electron in hydrogen as a uniform spherical volume charge density of radius r, what is the charge density of hydrogen ignoring the proton?

(b)A proton has a radius of about r = 1 x 10-15M. Modelling the charge of the proton as a uniform spherical volume charge density of radius r, what is the charge density of the proton?

Open-Response Homework Problem 1.4 In the activity using the charged rods that you just completed, it is not uncommon to build up a charge of almost a microCoulomb (say -0.9pC) on the golf tube by rubbing it with the oven roasting bag.

(a)How many electrons were transferred between the oven roasting bag and the golf tube? (b)Is the golf tube positively or negatively charged?

(c)Did the golf tube gain or lose electrons? Why?

(d)What was the charge on the oven roasting bag after it had been used to charge the golf tube? (e)What assumptions do you have to make to get the answer in (d)?