Physics 202 MWF 10:20 Spring 2004 (Ford)
Final Exam

Show all your work. Partial credit will be given if earned. Write your answers in the blanks provided.


(8 pts) 1. The isotope ⁶⁰Co has an atomic mass of 59.934 u and a half-life of 5.27 yr. A sample of ⁶⁰Co has an activity of 5.0 × 10¹⁴ Bq. What is the mass of the sample? (Note: 1 yr = 3.156 × 10⁷ s.)

Ans. __________________


(12 pts) 2.

a) A hollow spherical insulating shell of radius R = 0.40 m has a net charge q = +5.0 × 10^-9 C uniformly distributed over its surface. Point A is at the center of the shell and point B is at a distance of 0.20 m from the center of the shell. What is the potential difference V_A - V_B between points A and B?



Ans. ____________________

b) Two very large parallel conducting plates carry equal and opposite charges. The plates are separated by 0.0060 m. Point A is on the positively charged plate and point B is midway between the plates. If V_A - V_B = 80.0 V,what is



i) the magnitude and direction of the net electric field at point B due to the two plates. Show the direction of the electric field on the sketch.

Ans. E = __________________

direction _______________

ii) the magnitude of the charge per unit area on each plate.

Ans. ________________


(8 pts) 3. Consider the circuit shown in the sketch. After the capacitors have reached their final charge, the voltage across the 4.0× 10^-6 F capacitor is 8.0 V. What is the emf of the battery?



Ans. ________________


(8 pts) 4. In the circuit shown in the sketch, what is the total electrical power supplied by the battery? The battery has negligible internal resistance.



Ans. ________________


(8 pts) 5. Two long straight wires carry currents in opposite directions, as shown in the sketch. The two wires are separated by 0.40 m. What is the net magnetic field (magnitude and direction) at a point P, 0.20 m above the top wire?



Ans. B = ____________________

direction _________________

(8 pts) 6. A small particle with charge q = -5.0 × 10^-6 C moves to the right with speed v = 3.0 × 10⁵ m/s in a region of uniform magnetic and electric fields. The magnetic field has magnitude B = 0.80 T and is directed into the page, as shown in the sketch. The only forces on the particle are those due to the electric and magnetic fields. If the net force is zero, what are the magnitude and direction of the electric field? Show the electric field direction on the sketch.



Ans. E = _____________________

direction ____________________


(8 pts) 7. Consider the ac circuit shown in the sketch. The inductor has inductance L = 0.30 H. The amplitude of the voltage across the resistor is 80 V and the amplitude of the voltage across the inductor is 60 V. The amplitude of the current in the circuit is 4.0 A. What is the amplitude V₀ of the source voltage and what is the frequency f (in Hz) of the source?



Ans. V₀ = ___________________

f = _____________________


(8 pts) 8. An object 2.0 mm tall is to the left of a converging lens that has f = +40 cm. The image is to the left of the lens and has a height of 8.0 mm.

a) Is the image upright or inverted?

Ans. ______________________

b) How far is the object from the lens?

Ans. _________________


(8 pts) 9. A circular loop of wire with radius r = 0.20 m and resistance R = 0.80 is in a uniform magnetic field directed into the page as shown in the sketch. At t = 0 the magnetic field is B = 8.00 T and it then decreases at a constant rate of B/t = -0.50 T/s. What are the magnitude and direction of the induced current in the loop at t = 2.0 s? (The direction is either clockwise or counterclockwise.)



Ans. I = ___________________

direction __________________


(6 pts) 10. Two identical in-phase sources P and Q emit identical waves. Q is 4.00 m to the right of P. At point A midway between the two sources the interference of the waves from the two sources is constructive. As you move to the right from A, the first point where the interference is destructive is point B. Point B is 0.80 m to the right of point A. What is the wavelength of the waves?



Ans. ________________


(12 pts) 11. Point charge q₁ = +8.0 × 10^-6 C is on the x-axis at x = +0.30 m and point charge q₂ = -3.0 × 10^-6 C is on the -x-axis at x = -0.30 m.

a) What is the resultant electric field (magnitude and direction) at the origin due to the charges q₁ and q₂?

Ans. E = _______________

direction _______________

b) A small object with charge q₃ = -5.0 × 10^-6 C is initially on the +y-axis at a large distance from the origin. How much work is done on q₃ by the Coulomb forces exerted on it by q₁ and q₂ as q₃ moves along the y-axis to the origin.?

Ans. _______________

c) When q₃ = -5.0 × 10^-6 C is at the origin, what is the net force on it due to q₁ and q₂? Give both the magnitude and direction of the net force.

Ans. F = _____________________

direction _______________

(6 pts) 12. Find the binding energy (in MeV) for the lithium isotope ⁷₃Li (atomic mass = 7.016003 u).

Ans. ___________________