What is meant by the term 'Atmosphere'?

It is a liquid present on some planets

It is a hard shell of gases around planets

It is a temporary phenomenon due to solar radiations

It is a thin blanket of gases surrounding a planet or an object

Correct Answer : It is a thin blanket of gases surrounding a planet or an object

Explanation : The term ‘Atmosphere’ can be defined as a thin blanket of gases surrounding a planet or an object in outer space. As it is made up of gases, it cannot be a hard shell. It is not caused due to solar radiations.

Recently Updated in Spaceflight Mechanics Questions

Using Toussaint's formula, what is the temperature of air at a geopotential altitude of 4 km?

231 K

250 K

255 K

262 K

Correct Answer : Option (D) : 262 K

Explanation : Toussaint’s formula is given by T = 15 – 0.0065h
Where, T is the temperature in Celsius and h is the geopotential altitude in metres.
Therefore, T = 15 – 0.0065*(4000)
= – 11°C
= -11 + 273 K
= 262 K

U.S. Air Force defines the ____________ as the boundary between earth's atmosphere and space.

Karman line

Van Allen belt

Beginning of exosphere

Beginning of mesosphere

Correct Answer : Option (A) : Karman line

Explanation : The beginning of space is officially denoted at an altitude of 100 km which is also known as the Kármán line. After this line the aerodynamic effects are minimal. Cold gas thrusters are used to correct orientation after this line as aerodynamic control surfaces are useless.

What is the temperature of air if the pressure and density are 629.66 lb/ft² and 0.9408 x 10^-3 slug/ft³. Given specific gas constant is 1716 lb.ft/slug.⁰R.

125 ⁰R

225 ⁰R

250 ⁰R

390 ⁰R

Correct Answer : Option (D) : 390 ⁰R

Explaination : Given,
Pressure (p) = 629.66 lb/ft²
Density (ρ) = 0.9408 x 10^-3 slug/ft³
Specific gas constant (R) = 1716 lb.ft/slug.⁰R
Using equation of state,
Temperature, T = p/(ρR)
= 629.66/(0.9408*10^-3*1716)
= 390 ⁰R