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Question  A battery with an emf of 6

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Question  A battery with an emf of 6.00 V has an internal resistance r. When connected to a unknown resistor R₁, the terminal voltage is 5.90 V and the current is 0.16 A. When a second identical battery is added in series and the external resistor is R2= 13 Ohms the resulting current is:

0 1.5A

0 1.1 A

0 2A

0 0.63A

0 0.84A

 

Question 2

Two conductors are made of the same material. Conductor A is a hollow tube with inside diameter 2 mm and outside diameter 3 mm. Conductor B is a solid wire of unknown radius r and twice the length of conductor A. You are measuring the same resistance between the ends of the two conductors. What is the radius r of conductor B?

0 2.24 mm

0 1.58mm

0 0.79 mm

0 1.12 mm

 

Question 3

You are investigating the multiple resistance circuit shown in the figure. What is the equivalent resistance between points a and b if the resistor R₁ is replaced with an open switch?

0 R

0 1/R

0 2R

0 4R

Question 4

The capacitor in each circuit is first charged by a 10 V battery with no internal resistance. The switch is then flipped from position A to B and the capacitor is discharged through the resistor. For which circuit is the total energy dissipated by the resistor the largest?

 O a

O c

O b

O d

Question 5 1. Which of the following will reduce the time constant in an RC circuit?

O  Adding an additional resistor in parallel with the first resistor

O Adding an additional 20 m of wire between the capacitor and the resistor

O   Increasing the dielectric constant of the capacitor

0 None of the above

O Increasing the voltage of the battery

 

Question 6

A parallel plate capacitor of capacitance C has plates of area A with a distance d between them. When the capacitor is connected to a battery of potential difference V. it has a charge of magnitude Q on its plates. While the capacitor is connected to the battery, the distance between the plates is increased by a factor of 2.5. The magnitude of the charge on the plates and the capacitance become:

0 2.5 Q and 2.5 C

0 Q and 2.5 QC

0 0.4 Q and 2.5 C

0 2.5 Q and 0.4C

0 0.4 Q and 0.4 C

 

Question 7  An un-charged 4.90-µF capacitor is in series, through a switch, with a 6.05-M ?, resistor and a battery with negligible internal resistance. The switch is closed at t = 0 and a current 10 Immediately appears. How long will It take for the current In the circuit to drop to 0.37 of the Initial value I₀ ?

O 20.44 s O 42.99 s 0 14.1s 0 29.64 s 0 62.33 s

 

Question 8

A parallel-plate air capacitor is fully charged by a battery and has a charge Q on each plate. With the capacitor still connected to the battery, a dielectric material with k=4.5 is inserted so that it fills the volume between the plates. The ratio between the additional (not the total) charge flowing from the battery to the initial charge Q is:

0 1 0 5.5 0 2.5 0 4.5 0 3.5

Question 9

Consider the three situations 1, 2, and 3 of charged particles entering a magnetic field. In situation 1 the field points into the paper, while in situation 2 and 3 it point out of the paper. Which directions are the three charged particles deflected?

1 2 3

O To the top, to the left, to the top

O  To the top. to the left. to the bottom

O  To the bottom, to the right, to the bottom

O  To the top, to the right to the top

 

Question 10

If you connect a large number of 55 µF capacitors in parallel across a 140 V battery, how many capacitors do you need to store 44.7 J of energy?

0 19 0 27 0 57 0 0 39

Question 11

Two batteries are arranged in a circuit with two resistors as shown in the figure. The resistance of each resistor is not given, but the indicated currents are observed to flow through the two resistors. Which battery supplies the least power to the resistors?

0 the 30 V battery

0 it cannot be determined

0 both supply the same power

0 the 20 V battery

 

 

Question 12

A cylindrical conductive rod of mass 0.04 kg is placed across two parallel conducting tracks separated by 2 cm. and connected to a battery as shown. The current through the rod is 3 A. The whole setup sits on a horizontal platform in a region with a constant magnetic field of 1.2 T perpendicular to the plane of the tracks and oriented out of the page. What is the magnitude and the direction of the acceleration of the rod?

0 1.8 M/S² toward the battery

0 6.8 m/s2 toward the battery

O 0 9.8 m/52 away from the battery

0 1.8 M S2 away from the bane,

 

Question 13

A coaxial cable consists of a central wire of diameter R and a coaxial metal shielding of radius 2.5 R, separated by an insulating material. You used Gauss' law to find an expression for the capacitance per unit Length C/L. If the mains of me shielding is increased to 4.5 R, by what factor does the capacitance per unit lengh chance?

O 2  O 0.5  O 0.61  O 1.6

 

Question 14

A particle with mass m₁ and positive charge q travels with velocity v in the positive x direction. It enters into a region of uniform magnetic field B pointing out of the page and exits the region after describing a semicircle with radius R. Find the ratio m1 /m2 if the particle with mass m2 has the same velocity, three times the charge, enters the field at the same point, and describes a semicircle with half the radius R.

O 1/6      O 1/3      O ¼     O 2/3      O 3/2

 

Question 15

A DC circuit is shown below. Note the 'ground' (V=0) in the circuit. The magnitude of the potential at 'a’. is:

 

 O 0.471 V

 O 0.679 V

 O 0.417 v

 O 0.532 v

 O 0.601 v

 

Question 16     You made voltage-versus-current measurements for the three resistors in the circuit and have built the V versus I graphs. With the switch open, the steady-state equivalent resistance of the circuit is:

 

0 70 ?

 0 60 ?

0 20 ?

0 30 ?

0 10 ?