That quasars were at cosmological distances yet appeared like ordinary faint stars meant
A) they were the brightest stars ever observed.
B) they must be very large.
C) they must contain many O and B type stars.
D) they must be producing such large quantities of energy than even fusion could not explain their output.
E) they must be very small, but bright due to gravitational lensing.
D
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What is the minimum thickness of a glycerin film (n = 1.47) on which light of wavelength 684 nm shines that results in constructive interference of the reflected light? Assume the film is surrounded front and back by air
a. 233 nm b. 116 nm c. 251 nm d. 503 nm e. 126 nm
Three objects are connected by massless wires over a massless frictionless pulley as shown in the figure. The tension in the wire connecting the 10.0-kg and 15.0-kg objects is measured to be 133 N. What is the tension in wire A?
A) 87.5 N B) 245 N C) 280 N D) 333 N E) 517 N
A ball is thrown with an initial velocity of 20 m/s at an angle of 60° above the horizontal. If we can neglect air, what is the horizontal component of its instantaneous velocity at the exact top of its trajectory?
A) 10 m/s B) 17 m/s C) 20 m/s D) zero
The air we breathe is mostly oxygen
Indicate whether the statement is true or false