A radioactive substance containing 4.0 × 1016 unstable atoms has a half-life of 2.0 days. What is its activity (in curies, Ci) after 1.0 day? (1 Ci = 3.70 × 1010 Bq)
What will be an ideal response?
4.3 Ci
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If the temperature changes by 
then what is the change in temperature in Fahrenheit?
A. 27
B. 30
C. 32
D. 40
E. 47
Experiments have been performed on the temperature distribution in a homogeneous long cylinder (0.1 m diameter, thermal conductivity of 0.2 W/(m K) with uniform internal heat generation. By dimensional analysis, determine the relation between the steady-state temperature at the center of the cylinder Tc the diameter, the thermal conductivity, and the rate of heat generation. Take the temperature at the surface as you datum. What is the equation for the center temperature if the difference between center and surface temperature is 30°C when the heat generation is 3000 W/m3?
GIVEN
A homogeneous long cylinder with uniform internal heat generation
Diameter (D) = 0.1 m
Thermal conductivity (k) = 0.2 W/(m K)
Difference between surface and center temperature (Tc – Ts) = 30°C
Heat generation rate q = 3000 W/m3
FIND
(a) Relation between center temperature (Tc), diameter (D), thermal conductivity (k), and rate of heat
generation q
(b) Equation for the center temperature for the given data
ASSUMPTIONS
Steady state
One dimensional conduction in the radial direction
SKETCH
What is the energy of a photon that has the same wavelength as a 11.4-eV electron? (h = 6.63 × 10^?34 J?s, me = 9.11 × 10^–31 kg, 1 eV = 1.6 × 10^–19 J)
a. 1140 eV b. 32 eV c. 103 eV d. 3420 eV e. 1030 eV
A node is a position of
A) minimum amplitude. B) maximum amplitude. C) minimum frequency.