David Sang and Graham Jones Solutions for Chapter: Coulomb's Law, Exercise 6: EXAM-STYLE QUESTIONS

An $\alpha$-particle emitted in the radioactive decay of radium has a kinetic energy of $8.0\times {10}^{-13}J$.

(d) Suggest and explain what this information tells us about the gold nucleus.

(Mass of an $\alpha$ -particle $=6.65\times {10}^{-27} \mathrm{kg}$; charge on an $\alpha$ -particle $=+2e$; charge on a gold nucleus $=+79e$.)

(a) Define electric potential at a point.

This graph shows the electrical potential near an antiproton.

(i) Determine the potential at a distance $.053\times {10}^{-10}m$ from the antiproton.

(b) This graph shows the electrical potential near an antiproton.

(ii) Determine the potential energy a positron would have at this distance.

This diagram shows a conducting sphere of radius $0.80 \mathrm{cm}$ carrying a charge of $+6.0\times {10}^{-8}\mathrm{C}$ resting on a balance.

Calculate the electric field at the surface of the sphere.

This diagram shows a conducting sphere of radius $0.80 \mathrm{cm}$ carrying a charge of $+6.0\times {10}^{-8}\mathrm{C}$ resting on a balance.

(b) An identical sphere carrying a charge of $-4.5\times {10}^{-8}\mathrm{C}$ is held so that its centre is $5.0 \mathrm{cm}$ vertically above the centre of the first sphere.

(i) Calculate the electric force between the two spheres.

This diagram shows a conducting sphere of radius $0.80 \mathrm{cm}$ carrying a charge of $+6.0\times {10}^{-8}\mathrm{C}$ resting on a balance.

(b) An identical sphere carrying a charge of $-4.5\times {10}^{-8}\mathrm{C}$ is held so that its centre is $5.0 \mathrm{cm}$ vertically above the centre of the first sphere.

(ii) Calculate the new reading on the balance.

This diagram shows a conducting sphere of radius $0.80 \mathrm{cm}$ carrying a charge of $+6.0\times {10}^{-8}\mathrm{C}$ resting on a balance.

(c) The second sphere is moved vertically downwards through $1.5 \mathrm{cm}$. Calculate the work done against the electric field in moving the sphere.