Posted: May 9th, 2016

To an astronaut in orbit around the earth the sky appears

To an astronaut in orbit around the earth the sky appears
A) red.
B) blue.
C) white.
D) black.

When a real object is the distance f from a converging lens,
A) the image is virtual, erect, and larger than the object.
B) the image is real, inverted, and larger than the object.
C) the image is real, inverted, and the same size as the object.
D) no image is formed.

A current is flowing south along a power line. Neglecting the earth s field, the direction of the magnetic field under the power line is
a) north
b) south
c) east
d) west

The musical note A has a frequency of 440 Hz and its wavelength in seawater is 3.5 m. The speed of sound in seawater is
A) 80 m/s.
B) 126 m/s.
C) 1540 m/s.
D) 3 108 m/s.

An ideal frictionless engine takes in 10 kJ of heat per second when it operates between 500 K and 400 K. The work that the engine does per second is
A) 2 kJ.
B) 2.5 kJ.
C) 8 kJ.
D) 10 kJ.

Radio amateurs are permitted to communicate on the 10 meter band. What frequency of radio waves corresponds to a wavelength of 10 meters? The speed of radio waves is 3 108 m/s.
A) 3.3 X 10 8 Hz
B) 3.0 X 107
C) 3.3 X 10,sup>7 Hz
D) 3.0 X 109 Hz

A frequency that is not an overtone of the fundamental frequency F is
A) F/2.
B) 2F.
C) 3F.
D) 4F

When 90 kJ is removed from a 2 kg copper bar, its temperature drops from 200