What should be the height of a dipole antenna (of dimensions 1/4 wavelength) if it is to transmit 1200 kHz radiowaves?
a. 11.4 m
b. 60 cm
c. 1.12 m
d. 62.5 m
e. 250 m
d
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Which of the following wavelengths could NOT be present as a standing wave in a 2-m-long organ pipe open at both ends?
a. 4 m b. 2 m c. 1 m d. 0.89 m e. 0.5 m
The electric field just outside the surface of a hollow conducting sphere of radius 20 cm has a magnitude of 500 N/C and is directed outward. An unknown charge Q is introduced into the center of the sphere and it is noted that the electric field is still directed outward but has decreased to 100 N/C. What is the magnitude of the charge Q?
a. 1.5 nC b. 1.8 nC c. 1.3 nC d. 1.1 nC e. 2.7 nC
Spectral lines shifted toward higher frequencies are called ________.
A. red shifted B. blue shifted C. Lines cannot be shifted toward higher frequencies.
At the end of its life, what kind of pressure will support our Sun?
A) neutron degeneracy pressure B) quark degeneracy pressure C) electron degeneracy pressure D) pressure from interstellar dust particles