11. A major belt of asteroids is located between Mars and Jupiter. What is the approximate average distance between the Sun and this major asteroid belt?

A) 110 million kilometers

B) 200 million kilometers

C) 800 million kilometers

D) 390 million kilometers

Correct Answer: Option D - 390 million kilometers

From Earth Science Reference table, we have the following data:

• Mars is at a mean distance of 227.9 million kms from Sun

• Jupiter is at a mean distance of 778.3 million kms from Sun

Since the asteroid belt is located between Mars and Jupiter, from the above given options, option D is most appropriate answer for average distance to be approximately 390 million kms, since this option is in between the mean distances between Mars and Jupiter.

Hence, options A,B and C are incorrect.

12. Which planet has an orbital eccentricity most like the orbital eccentricity of the Moon?

A) Pluto

B) Mars

C) Saturn

D) Mercury

Correct Answer: Option C – Saturn

Any orbit must be of conic section shape. The eccentricity of this conic section, the orbit's eccentricity, is an important parameter of the orbit that defines its absolute shape. Eccentricity may be interpreted as a measure of how much this shape deviates from a circle.

Under standard assumptions eccentricity (e) is strictly defined for all circular, elliptic, parabolic and hyperbolic orbits and may take following values:

• for circular orbits: e = 0

• for elliptic orbits: 0 < e <1

• for parabolic trajectories: e = 1

• for hyperbolic trajectories: e >1

Thus e=0 would describe a perfectly circular orbit. For greater values of e such that e <1 the orbit would assume the shape of an increasingly elongated (or flatter) ellipse.

o Saturn has an eccentricity of 0.055723219

o Moon has an eccentricity of 0.0549

Incorrect Options

• Pluto has an eccentricity of 0.24880766

• Mars has an eccentricity of 0.093315

• Mercury has an eccentricity of 0.205630

16. Which planet’s orbit around the Sun is most nearly circular?

A) Mercury

B) Neptune

C) Pluto

D) Venus

Correct Answer: Option C – Pluto

Any orbit must be of conic section shape. The eccentricity of this conic section, the orbit's eccentricity, is an important parameter of the orbit that defines its absolute shape. Eccentricity may be interpreted as a measure of how much this shape deviates from a circle.

Under standard assumptions eccentricity (e) is strictly defined for all circular, elliptic, parabolic and hyperbolic orbits and may take following values:

• for circular orbits: e = 0

• for elliptic orbits: 0 < e <1

• for parabolic trajectories: e = 1

• for hyperbolic trajectories: e >1

Thus e=0 would describe a perfectly circular orbit. For greater values of e such that e <1 the orbit would assume the shape of an increasingly elongated (or flatter) ellipse.

The planets all orbit the Sun close to a flat reference plane called the ecliptic and have nearly circular orbits. In contrast, Pluto's orbit is highly inclined relative to the ecliptic (over 17°) and highly eccentric (elliptical).

The following are the eccentricities of planets:

• Mercury 0.2056

• Venus 0.0068

• Neptune 0.0086

• Pluto 0.2482

17. Which star’s surface temperature is closest to the temperature at the boundary between Earth’s mantle and core?

A) Sirius

B) The Sun

C) Rigel

D) Betelgeuse

Correct Answer: Option B – The Sun

The resulting temperature at the core-mantle boundary of about 4000 K then requires a large temperature gradient at the bottom of the lower mantle of about 1500 K.

Sun has a surface temperature of 5,778 K.

Incorrect Options

• Betelgeuse has a surface temperature of 3,500 K.

• Sirius has a surface temperature of 25,200 K.

• Rigel has a surface temperature of 11,000K.