Someone has sent me a copy of mini exam one from PHY2054: Here are the problems they sent me. They do look authentic.

Problem 1: An ion accelerated through 300.00 V has its potential energy decreased by a potential energy of 9.6E-17 J.

a) Calculate the charge on the ion (5pts)

b) What will be the speed of the ion after it has accelerated through the potential change above if it starts from rest? The ion has a mass of 1.00E-26 kg (5pts)

Problem 2: AS commercial capacitor is constructed with foil and paper. This particular capacitor is made from aluminum foil separated by two strips of paraffin coated paper. The overlap b/w each strip of foil separated by the paper is 7.00 cm wide. The foil is 0.00400 mm thick, and the paper is 0.025 mm thick and has a dielectric constant of 3.7.

a) What length should the strips be if a capacitance is 6.5E-8 F is desired before the capacitor is rolled up? (adding the second strip of paper and rolling up the capacitor doubles the capacitance by allowing both surfaces of each strip of foil to store charge, but this doubling is not included in our problem)

Prblem 3: A point charge with q1=-1.6 C is located at x= -3.0 m, y=0, a second point charge with q2=+3.6 C is at x=0.0 m, y=+4.0 m (HINT: measure all angles starting counterclockwise from the + x direction)

a) What is the magnitude and direction of the electric field caused only by q1 (6pts)

b) Find the magnitude and direction of the electric force at the origin caused by q2.(6pts)

c) Find the vector sum of the two fields found above, giving the magnitude and direction(6pts)

d) If a single electron were placed at the origin, what would be the magnitude and direction of the force on it caused by the presence of the other two charges? (6pts)

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Problem 1: An ion accelerated through 300.00 V has its potential energy decreased by a potential energy of 9.6E-17 J.

a) Calculate the charge on the ion (5pts)

b) What will be the speed of the ion after it has accelerated through the potential change above if it starts from rest? The ion has a mass of 1.00E-26 kg (5pts)

Problem 2: AS commercial capacitor is constructed with foil and paper. This particular capacitor is made from aluminum foil separated by two strips of paraffin coated paper. The overlap b/w each strip of foil separated by the paper is 7.00 cm wide. The foil is 0.00400 mm thick, and the paper is 0.025 mm thick and has a dielectric constant of 3.7.

a) What length should the strips be if a capacitance is 6.5E-8 F is desired before the capacitor is rolled up? (adding the second strip of paper and rolling up the capacitor doubles the capacitance by allowing both surfaces of each strip of foil to store charge, but this doubling is not included in our problem)

Prblem 3: A point charge with q1=-1.6 C is located at x= -3.0 m, y=0, a second point charge with q2=+3.6 C is at x=0.0 m, y=+4.0 m (HINT: measure all angles starting counterclockwise from the + x direction)

a) What is the magnitude and direction of the electric field caused only by q1 (6pts)

b) Find the magnitude and direction of the electric force at the origin caused by q2.(6pts)

c) Find the vector sum of the two fields found above, giving the magnitude and direction(6pts)

d) If a single electron were placed at the origin, what would be the magnitude and direction of the force on it caused by the presence of the other two charges? (6pts)

Feel free to leave a comment