Ch24_1
New Problems
reloads the page with new variable values in all questions. You must do this after grading the test to rework it another time.
Make sure to enter your answers in the specified units .
1) What is the number of iron (density=7.88
grams/cm
3
) atoms in a cube cm on a side
(see sheet 2,3,5
;
use 55.8 u for the atomic mass of iron
)
? Indicate with a negative (positive) sign whether the result would be the same (different) for the same number of moles of Uranium.
2) X-Rays with a wavelength of nm are scattered from a crystal with a distance of nm between the crystal planes. At which scattering angle does the first order diffraction maximum occur ?
(sheet 9,11,
the scattering angle is not the same angle which occurs in the maxumum condition!
)
3) An electron beam enters a region where a uniform electric and a uniform magnetic field are perpendicular to each other. The electron beam is perpendicular to both fields. What is the magnetic field if the electrons traverse undeflected with a speed of x10
6
m/s and the electric field is N/C
(see sheets 12,13,16)
? Indicate with a negative (positive) sign whether the same (a different) magnetic field would be needed for a proton beam with the same direction and speed as the electron beam.
4) An electron (mass =9.11x10
-31
kg
) beam with a speed of x10
6
m/s enters a region of uniform magnetic field of x10
-4
T. The electron beam is perpendicular to the field. What is the radius of the electron circular path in the field
(see sheet 13,16)
? Indicate with a positive (negative) sign whether the magnetic force is (is not) parallel to the magnetic field.
5) An oildrop with a mass of x10
-15
kg and a charge of -x10
-18
C on it is suspended between capacitor plates with a cm distance between them. What is the electric field
(sheet 17)
? Indicate with a positive (negative) sign whether the field points up (down).
6) In a Millikan type experiment a charge of x10
-18
C is measured for the oildrop. How many electrons carry this charge
(sheet 19)
? Do not round to get an integer number. Indicate with a positive (negative) sign whether this number corresponds to the number of excess electrons (the total number of electrons) contained in the drop.
Once you have submitted your answers for grading by clicking the grade button, you
cannot resubmit answers
for the same Problem Set--you must use the 'New Problems' button first.
Need help? Try these test-taking tools:
Constants
Conversions
calculator