Total # Posts: 12
A 40 W (120V) light bulb has a tungsten filament of thickness 0.035 mm. The filament's operating temperature is 1500 degrees C. PART A How long is the filament? PART B What is the resistance of the filament at 20 degrees C?
March 14, 2010
Air isn't a perfect electric insulator, but it has a very high resistivity. Dry air has a resistivity of approximately 3 x 10^13 Ù x m. A capacitor has square plates 10 cm on a side separated by 1.2 mm of dry air. If the capacitor is charged to 250 V, what fraction ...
March 13, 2010
Two 2.5-cm-diameter electrodes with a 0.10-mm-thick sheet of Teflon between them are attached to a 9.0V battery. Without disconnecting the battery, the Teflon is removed. a) What is the charge before the Teflon is removed? Q= C b) What is the potential difference before the ...
March 8, 2010
In the early 1900s, Robert Millikan used small charged droplets of oil, suspended in an electric field, to make the first quantitative measurements of the electrons charge. A 0.67-um-diameter droplet of oil, having a charge of +e, is suspended in midair between two ...
March 6, 2010
Use Unit Conversions 1 atm = 760 torr (2.48*10^-3 atm)(760 torr/1 atm)= -1.488*10^-1 4.75*10^6 atm (760 torr/1 atm)= 3.61*10^9 Can't solve the third one cause u didn't include units...hope this helps!!
March 6, 2010
A stereo amplifier creates a 3.5 V potential difference across a speaker. To double the power output of the speaker, the amplifier's potential difference must be increased to: A. 7.0 V B. 9.9 V C. 12 V D. 4.9 V
March 5, 2010
Two uncharged metal spheres, spaced 20.0 cm apart, have a capacitance of 28.0 pF. How much work would it take to move 14.0 nC of charge from one sphere to the other? *Please report answer in Joules.
March 3, 2010
An uncharged capacitor is connected to the terminals of a 3.0 V battery, and 9.0 uC flows to the positive plate. The 3.0 V battery is then disconnected and replaced with a 8.0 V battery, with the positive and negative terminals connected in the same manner as before. How much ...
March 3, 2010
In daylight, the diameter of the iris is about 3 mm. PART A What is the angle between two distant point objects that can just be resolved? Assume the light's wavelength in air is 600 nm and the index of refraction inside the eye is 1.33. PART B What is the distance on the ...
February 14, 2010
Problem 19.33 Two light bulbs are 1.5 m apart. From what distance can these light bulbs be marginally resolved by a small telescope with a 4.0 cm-diameter objective lens? Assume that the lens is limited only by diffraction and lambda = 600 nm.
February 12, 2010