Suppose a planet is discovered by the doppler technique and is then discovered to have transits. in that case, we can determine all the following about the planet except
a) its rotation period
b) its orbital period
c) its physical size (radius)
d) its precise mass
e) its density

option A

Explanation:

The correct answer is option A

Doppler technique is used in sound as well as light. Scientist uses this technique to study the universe by determining how fast stars and galaxies.

Transit is a phenomenon takes place when celestial body celestial passes directly between a larger body and the observer.

Using the Doppler effect we can determine the characteristics of the planet like the orbital period of the planet, size of the planet, mass and density of the planet.

The characteristics of the planet which we cannot find are The rotational period.

answer: the exterior temperature of commercial jet planes as they leave the stratosphere and return to the ground increases steadily.

explanation:

the lower most layer of atmosphere is troposphere which extends from 0 to 12 km above the surface of the earth. the temperature initially decreases as distance is increased from the earth's surface. commercial jets fly in lower part of the stratosphere. the stratosphere extends upto 50 km. the temperature in stratosphere starts rising again due to presence of ozone which traps the uv rays.

thus, when the planes leave the stratosphere and return to the ground, the exterior temperature increases steadily.

the current is 0.6

voltage ÷ resistance = current

so 12 ÷ 20 = 0.6