Exam 21: Electric Charge

A small object has charge Q.Charge q is removed from it and placed on a second small object.The two objects are placed 1 m apart.For the force that each object exerts on the other to be a maximum, q should be:

The leaves of a positively charged electroscope diverge more when an object is brought near the knob of the electroscope.The object must be:

Charge is distributed uniformly on the surface of a spherical nonconducting shell.A point particle with charge q is inside.The electrical force on the particle q is least when:

One type of medical imaging process is called positron emission tomography.Radioactive material is injected into a patient; during the radioactive decay the material emits a positron, which then interacts with an atomic electron, emitting gamma rays, which are detected by the imager.This gamma ray emission process is called:

A kiloampere . hour is a unit of:

Particle 1 with charge q₁, and particle 2, with a charge q_2, are on the x axis, with particle 1 at x = a with and particle 2 at x = -2a.For the net force on a third charged particle, at the origin to be zero q₁ and q₂ must be related by q₂=:

A particle with a charge of 5 *10^-6 C and a mass of 20 g moves uniformly with a speed of 7 m/s in a circular orbit around a stationary particle with a charge of -5* 10^-6 C.The radius of the orbit is:

A coulomb is the same as:

To make an uncharged object have a positive charge:

Two particles, each with charge Q, and a third particle, with a charge q, are placed at the vertices of an equilateral triangle as shown.The total force on the particle with charge q is:

A positively charged insulating rod is brought close to an object that is suspended by a string.If the object is repelled away from the rod we can conclude: