#phys7b

Suppose electrons enter a uniform electric field midway between two plates at an angle θ0 to the horizontal, as shown in the figure (Figure 1). The path is symmetrical, so they leave at the same angle θ0 and just barely miss the top plate.

What is θ0? Ignore fringing of the field.

An electron has an initial velocity v0 = (9.0×104m/s) j . It enters a region where E^=(1.9 i + 7.4 j)×10^4 N/C.

a) Determine the vector acceleration of the electron as a function of time.

b) At what angle θ is it moving (relative to its initial direction) at t = 1.4 ns ? (counterclockwise from the initial direction)

a) Use Coulomb's law to determine the magnitude of the electric field at points A and B in the figure (Figure 1) due to the two positive charges (Q = 4.7 μC , a = 5.5 cm ) shown.

b) Use Coulomb's law to determine the direction of the electric field at points A and B

c) Are your results consistent with Fig.21-34b in the textbook?

You are given two unknown point charges, Q1 and Q2 . At a point on the line joining them, one-third of the way from Q1 to Q2 , the electric field is zero (see the figure (Figure 1)).

What is the ratio Q1/Q2?

a) Determine the magnitude of the electric field E at the origin 0 in the figure (Figure 1) due to the two charges at A and B.

b) Determine the direction of the electric field E at the origin 0 in the figure due to the two charges at A and B.

c) Repeat A, but let the charge at B be reversed in sign.

d) Repeat B, but let the charge at B be reversed in sign.

Two small charged spheres hang from cords of equal length ℓ as shown in the figure (Figure 1) and make small angles θ1 and θ2 with the vertical.

a) If Q1=Q, Q2=3Q, and m1=m2=m, determine the ratio θ1/θ2.

b) If Q1=Q, Q2=3Q, and m1=m, and m2=3m, determine the ratio θ1/θ2.

c) Estimate the distance between the spheres for the case Q1=Q, Q2=3Q, and m1=m2=m.

d) Estimate the distance between the spheres for the case Q1=Q, Q2=3Q, and m1=m, and m2=3m.

One mole of monatomic gas undergoes a Carnot cycle with TH = 400 ∘C and TL = 240 ∘C. The initial pressure is Pa = 8.1 atm (see Figure 20-7 in the textbook). During the isothermal expansion, the volume doubles.

a) Find the values of the pressure at the points a, b, c, d

b) Find the values of the volume at the points a, b, c, d

d) Determine W for each segment of the cycle

A Carnot engine performs work at the rate of 570 kW with an input of 990 kcal of heat per second.

If the temperature of the heat source is 560 ∘C, at what temperature is the waste heat exhausted?