In the Mapping of Venus by the Orbiting Magellan Spacecraft

question 245

Multiple Choice

In the mapping of Venus by the orbiting Magellan spacecraft, what parameter was measured by the sensors in order to produce three-dimensional maps of the planet's surface?

• A) precise photographs of the extreme limb of the planet, taken at UV wavelengths to which the atmosphere is transparent, that showed detailed profiles of the planet's surface
• B) time delay of the return of reflected radio waves
• C) wavelength and hence Doppler shift of reflected radio waves
• D) pairs of photographs taken from different angles that were then combined stereoscopically to produce contour maps

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Definitions:

Pitch

The perceived frequency of a sound, determining how high or low it seems.

Hertz

The unit of frequency in the International System of Units (SI), defined as one cycle per second.

Loudness

A perceptual attribute of sounds that indicates the intensity or volume, as perceived by the ear.

Decibels

A unit used to measure the intensity of sound, with higher decibels indicating louder sounds.