In Millikan's oil drop experiment, if the electric field between the plates was of just the right magnitude, it would exactly balance the weight of the drop. Suppose a tiny spherical oil droplet of radius 1.3 × 10^?4 cm carries a charge equivalent to one electron. What electric field is required to balance the weight? (The density of oil is 0.85 g/cm3, e = 1.6 × 10^?19 C.)
a. 3.8E+6 N/C
b. 6.0E+4 N/C
c. 9.4E+2 N/C
d. 4.8E+5 N/C
e. 1.3E+7 N/C
d
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A) 50 Hz B) 200 Hz C) 25 Hz D) 100 Hz
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A wheel rotating about a fixed axis has a constant angular acceleration of 4.0 rad/s2 . In a 4.0-s interval the wheel turns through an angle of 80 radians. Assuming the wheel started from rest, how long had it been in motion at the start of the 4.0-s interval?
a. 2.5 s b. 4.0 s c. 3.5 s d. 3.0 s e. 4.5 s
An atomic nucleus has a charge of +40e. What is the magnitude of the electric field at a distance of 1.0 m from the center of the nucleus? (k = 1/4??0 = 8.99 × 109 N • m2/C2, e = 1.60 × 10-19 C)
A) 5.4 × 10-8 N/C B) 5.6 × 10-8 N/C C) 5.8 × 10-8 N/C D) 6.0 × 10-8 N/C E) 6.2 × 10-8 N/C