Light of wavelength 633 nm from a He-Ne laser passes through a circular aperture and is observed on a screen 4.0 m behind the aperture. The diameter of the central bright area is 5.4 cm. What is the diameter of the aperture?
A) 2.0 ?m B) 960 ?m C) 110 ?m D) 6600 ?m
C
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Microfossils found in northwestern Australia in 2011 appears to have used compounds based on which element for metabolism?
A) sulfur B) oxygen C) nitrogen D) carbon
An RC circuit is connected across a DC voltage source through an open switch. As soon as the switch is closed, the capacitor charges linearly as a function of time
Indicate whether the statement is true or false
Calculate the temperature drop from the center line to the surface for a 2.5 cm diameter rod having a thermal conductivity of 26 W/(m K) if the rate of heat removal from its surface is 1.6 MW/ m2 .
In a cylindrical fuel rod of a nuclear reactor, heat is generated internally according to the
equation
GIVEN
• A cylindrical rod with internal generation and heat removal from its surface
• Outside diameter (Do) = 2.5 cm=0.025 m
• Rate of heat generation is as given above
• Thermal conductivity (k) = 26 W/(m K)
• Heat removal rate (q/A) = 1.6 MW/m2
FIND
• The temperature drop from the center line to the surface (?T)
ASSUMPTIONS
• The heat flow has reached steady state
• The thermal conductivity of the fuel rod is constant
• One dimensional conduction in the radial direction
SKETCH
A box is launched up a frictionless incline with an angle of elevation ?. The maximum height reached by the box is h. The box is again launched up the incline with the same initial speed it had before, but this time the angle of elevation has been increased to ?. How does the maximum height H reached this time by the box compare with the previous value h?
a. H = h b. H > h c. H < h d. H = ((sin?)/(sin?))