Physics Answers

Experiment 1

Materials: salt, fine pepper, small dish, plastic comb, wool/cotton cloth.

Procedure:

1. Put the salt and fine pepper separately in a small dish

2. Rub the plastic comb with cloth repeatedly.

3. Hover the comb over the salt and fine pepper.

Questions:

1. What do you think is the charge of the salt and fine pepper in step 1?

2. What do you think is the charge of the comb in step 2?

3. explain what happened in the experiment.

The relative permittivity of a die electric is 2.25.(a) What is its permittivity (b) What will be the capacitance of this electric is inserted into a 7.8 air capacitor?

If the speed of the bob at the lowest point A is 0.84 m/s, what is its KE at this point?

1.A beam of light enters water at an angle of 60 degrees relative to the normal of the water surface . Find the angle of refraction?

2.Light passes from air into water . If the angle of refraction is 20° ,what is the index of refraction of the plastic?

A small particle has charge -5.00 uC and mass

2.00 x 10-4 kg. It moves from point A, where the electric poten-

tial is VA = +200 V, to point B, where the electric potential is

VB = +800 V. The electric force is the only force acting on the

particle. The particle has speed 5.00 m/s at point A. What is its

speed at point B? Is it moving faster or slower at B than at A?

A point charge q1, is held stationary at the origin. A second charge q2 is placed at a point a, and the electric potential energy of the pair of charges is −6.4×10 −8J. When the second charge is moved to point b, the electric force on the charge does 4.2×10 −8 J of work. What is the electric potential energy of the pair of charges when the second charge is at point b?

A charge of 28.0 nC is placed in a uniform electric field

that is directed vertically upward and has a magnitude of

4.00 104 V/m. What work is done by the electric force when

the charge moves (a) 0.450 m to the right; (b) 0.670 m upward;

(c) 2.60 m at an angle of 45.0° downward from the horizontal?

Three nano coulombs (nC) are placed at a seperate corner of a square with each side measuring 3cm. The two charges located at opposite vertices are negative, and other given charge is positive. Calculate the force experienced by a fourth 3nC when place at the missing corner. What is it orbital period and what its radial acceleration?

What is the strength of the electric fold 1mm away from a 38uc

charge? la 24 charge is placed in this fold at this distance, what

will be the force on it.

The electric potential at a distance of 0.92m from a point charge is -8.41x10^5 V. what is the

quantity of the point charge?