After being charged from a battery, the plates of a parallel plate capacitor are moved closer together. When they are half as far apart as originally, by how much does the stored energy change?
What will be an ideal response?
The capacitance doubles but charge remains the same so energy, Q2/(2C), reduces to half of what it was.
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An aluminum wing on a plane is 38 m long when the temperature is 20 oC. At what temperature (in oC) would the wing be 0.04 m shorter? Enter your answer to one decimal place. You should think about the physics of the situation before trying to solve the problem. (Hint: You are being asked for a temperature, not a temperature change)
In walking barefoot on red-hot coals, to prevent bits of coal sticking to your feet, it would be safer if your feet are
A) wet. B) dry. C) either of these D) none of the above
In the tensile test of single crystals, the proportional limit stress is not constant; the _____________ is constant.
Fill in the blank(s) with the appropriate word(s).
Charge of uniform density (80 nC/m3) is distributed throughout a hollow cylindrical region formed by two coaxial cylindrical surfaces of radii 1.0 mm and 3.0 mm. Determine the magnitude of the electric field at a point which is 2.0 mm from the symmetry axis
a. 7.9 N/C b. 9.0 N/C c. 5.9 N/C d. 6.8 N/C e. 18 N/C