Cheat Sheet 2-physics 2 3r2a3v

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A parallel-plate capacitor has circular plates of 6.50 cm radius and 1.90 mm separation. (a) Calculate the capacitance. (b) What charge will appear on the plates if a potential difference of 120 V is applied? A 200 pF capacitor is charged to a potential difference of 70 V, and the charging battery is disconnected. The capacitor is then connected in parallel with a second (initially uncharged) capacitor. If the potential difference across the first capacitor drops to 46 V, what is the capacitance of this second capacitor? A 2.0 µF capacitor and a 6.0 µF capacitor, are connected in parallel across a 400 V potential difference. Calculate the total energy stored in the capacitors. In the figure below, V = 9.0 V, C1 = C2 = 32 µF and C3 = C4 = 16 µF. What is the charge on C4? A coil is formed by winding 250 turns of insulated 14 gauge copper wire (diameter = 1.6 mm) in a single layer on a cylindrical form of radius 12 cm. What is the resistance of the coil? The resistivity of copper is 1.69 10-8 ·m. Neglect the thickness of the insulation. A conducting wire has a 1.5 mm diameter, a 2.0 m length, and a 70 mΩ resistance. What is the resistivity of the material? A wire with a resistance of 10.0 is drawn out through a die so that its new length is twice its original length. Find the resistance of the longer wire, assuming that the resistivity and density of the material are unchanged. Two conductors are made of the same material and have the same length. Conductor A is a solid wire of diameter 1.0mm. Conductor B is a hollow tube of outside diameter 6.0 mm and inside diameter 3.0 mm. What is the resistance ratioRA/RB, measured between their ends? A 114 V potential difference is applied to a space heater whose resistance is 12

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A piece of copper is made into a rod with a square cross section. The side of the square is 2.00 centimeters. The resistivity of copper is

1.7 ×10−8 Ω ∙m

. The length of the

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rod is 5 meters and an unknown electric field is directed along the rod, creating a current of 12.0 amperes. A. What is the resistance of the rod? B. What is the potential difference across the rod? C. What is the magnitude of the electric field? D. How much energy is lost to heat in one hour? Look at the diagram below:

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A. What is the equivalent capacitance of the circuit? B. What is the charge on each capacitor? C. What is the total energy stored within the capacitors? Look at the figure below: NOTE: 1k=1000 Ohms

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What are the values of all the currents flowing within this circuit? B. What is the power supplied by the second battery? (V2) Look at the RC circuit below:

when hot.

In the figure below, the ideal batteries have emfs 1

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= 12 V,

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= 6.0 V, and the resistors have

resistances R1 = 4.0 and R2 = 7.0 . In the figure below, circuit section AB absorbs energy at a rate of 50 W when current i = 1.5 A through it is in the indicated direction. Resistance R = 2.0 .(a) What is the potential difference between A and B? Emf device X lacks internal resistance. (b) What is the emf of device X? What multiple of the time constant τ gives the time taken for an initially uncharged capacitor in an RC series circuit to be charged to 71.0% of its final charge? In the figure below, the ideal battery has emf

= 24 V,

the resistances are R1 = 25 k the capacitor is uncharged.

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and R2 = 10 k

In the figure below, R1 = R2 = 15.0

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Immediately after switch 1 is closed and switch 2 is left open, what is the current through R1 and the charge on the capacitor (C1)? B. What is the charge on the capacitor after 100 ms? C. After a long time, what is the energy stored in the capacitor? D. Once the capacitor is fully charged, switch 1 is opened and switch 2 is closed. What is the magnitude of the current through the circuit containing only the resistor and the capacitor after 50 ms? Look at the image below:

, and the ideal

battery has emf = 6.0 V. (a) What value of R3 maximizes the rate at which the battery supplies energy? (b) What is that maximum rate?

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Immediately after the switch is closed, what are the currents through each resistor? The switch has been closed for a long time, what are the