In a color television tube, electrons are accelerated through a potential difference of 20000 volts. With what velocity do the electrons strike the screen?
v = 0.27c
You might also like to view...
Light from an astronomical source is found to be shifted to a one percent lower frequency than had the source been at rest. What radial velocity could cause such a shift?
A. 
m/s moving away from the observer
B. 
m/s moving away from the observer
C. 
m/s moving toward the observer
D. 
m/s moving toward the observer
E. 
m/s moving away from the observer
Light of wavelength 400 nm bombards a surface with work function 2.46 eV. What is the maximum kinetic energy of the photoelectrons from this surface?
A. no photoelectrons are emitted B. 2.46 eV C. 3.30 eV D. 0.640 eV E. 0.840 eV
The rate of heat flow per unit length q/L through a hollow cylinder of inside radius ri and outside radius ro is q/L = ( A k ?T)/(ro – ri) where A = 2? (ro – ri)/ln(ro/ri). Determine the per cent error in the rate of heat flow if the arithmetic mean area ? (ro + ri) is used instead of the logarithmic mean area A for ratios of outside to inside diameters (Do/Di) of 1.5, 2.0, and 3.0. Plot the results.
GIVEN
• A hollow cylinder
• Inside radius = ri
• Outside radius = ro
• Heat flow per unit length as given above
FIND
(a) Per cent error in the rate of heat flow if the arithmetic rather than the logarithmic mean area is used for ratios of outside to inside diameters of 1.5, 2.0, and 3.0. (b) Plot the results
ASSUMPTIONS
• Radial conduction only
• Constant thermal conductivity
• Steady state prevails
SKETCH
What is responsible for much of the erosion of Earth's surface?
a. lava flows b. solar wind c. impact craters d. convection e. water