The classification of stellar spectra started with the amount of hydrogen in the star's spectrum; however, now a better scheme uses the star's _____
a. mass
b. diameter
c. radius
d. temperature
e. luminosity
d
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Intensity: A sinusoidal electromagnetic wave has a peak electric field of 8.00 kV/m. What is the intensity of the wave? (c = 3.0 × 108 m/s, ?0 = 4? × 10-7 T ? m/A, ?0 = 8.85 × 10-12 C2/N ? m2)
A. 170 kW/m2 B. 85 kW/m2 C. 21 kW/m2 D. 11 kW/m2
When we look at pictures of distant objects in the universe, the images of the objects often are distorted by gravitational lensing
Indicate whether the statement is true or false
A charged particle moves in a region of uniform magnetic field along a helical path (radius = 4.0 cm, pitch = 20 cm, period = 2.0 ms). What is the speed of the particle as it moves along this path?
A. 0.13 km/s B. 0.10 km/s C. 0.16 km/s D. 0.23 km/s E. 0.06 km/s
An object of mass 10.0 kg is initially at rest. A 100 N force causes it to move horizontally through a distance of 6.00 m. What is the change in the kinetic energy of this object?
A) 0 J B) 200 J C) 60.0 J D) 600 J E) 1000 J