Early and modern theories

Correct answer: B. A rotating hot gaseous nebula

Kant explained the Sun and planets from a rotating gaseous nebula. For exams, connect nebula with a gas cloud.

Correct answer: D. Rings separated from a contracting nebula to form planets

Laplace proposed rings separating from a contracting nebula. In exams, link the ring idea with Laplace.

Correct answer: A. Accumulation of small solid planetesimals

This hypothesis says small planetesimals combined to form larger planets. For exams, treat planetesimals as small solid bodies.

Correct answer: C. Gravitational pull of a passing star

The tidal theory suggests a passing star pulled matter from the Sun. In exams, connect tidal force with an external star.

Correct answer: B. Extremely hot and dense state

The Big Bang theory connects the universe with an extremely hot and dense beginning. For exams, expansion is its key feature.

Correct answer: C. Red shift of distant galaxies

Red shift shows that distant galaxies are moving away from us. In exams, write red shift as evidence of universal expansion.

Correct answer: D. It considers the universe nearly unchanged over time

The steady state theory assumes the universe remains almost the same on average over time. In exams, contrast it with the evolutionary idea of the Big Bang.

Correct answer: A. Planet formation from a cloud of gas and dust

Both ideas link planet formation to cloud-like material. For exams, understand solar nebula as a source of gas and dust.

Correct answer: B. Accretion of gas and dust cloud

These ideas explain planets through accretion of gas and dust around the Sun. In exams, connect this with the modern solar nebula view.

Correct answer: D. It emphasizes joining of small solid bodies

The planetesimal hypothesis emphasizes the accumulation of small solid bodies. For exams, see it as a growth process of solid particles.

Correct answer: C. After a great explosion-like initial event

In the Big Bang idea, expansion began after an extremely hot and dense initial event. In exams, link it with the origin of the universe, not only Earth.

Correct answer: A. Small particles joining to form larger bodies

In accretion, small particles collide and combine to form larger bodies. For exams, it is the growth process of planet formation.

Correct answer: D. Because matter collects in this disk to form planets

The flat disk of the solar nebula became the region of planet formation. In exams, treat the disk as the birthplace of planets.

Correct answer: B. They could not explain several physical processes adequately

Many early theories were attractive but could not fully explain issues like energy and angular momentum. In exams, remember limitations too.

Correct answer: C. The universe is expanding

The shift of light from distant galaxies toward red shows that they are moving away. For exams, take it as evidence of expansion.

Correct answer: A. Basic particles and light elements

After the Big Bang, basic particles and light elements formed first, followed by larger bodies. For exams, remember the order from small to large.

Correct answer: B. A large body developing during planet formation

A protoplanet is a body growing toward becoming a planet through accretion. In exams, understand it as an early form of a planet.

Correct answer: A. Collapse of the same huge gas-dust cloud

The modern theory says the Sun and planets formed from the collapse of the same gas-dust cloud. For exams, remember the common source.

Correct answer: C. Tidal theory

The tidal theory assumes that a passing star pulled matter from the Sun by gravity. In exams, a passing star is the clue.

Correct answer: D. Because it was proposed in an era of limited scientific knowledge and telescopic observations

The nebular hypothesis was proposed before modern space science. In exams, study early theories in their historical context.

Correct answer: B. Big Bang theory

Cosmic microwave background is considered leftover radiation from the Big Bang. In exams, mention it as major evidence for the Big Bang.

Correct answer: A. They formed from a flat rotating solar disk

Planets formed in a flat rotating disk orbit nearly in the same plane. In exams, connect the orbital plane with disk structure.

Correct answer: A. Steady state theory

The steady state theory treats the universe as always similar on average. In exams, contrast it with the Big Bang.

Correct answer: C. Cooling matter changing into small solid or liquid particles

In condensation, hot gas cools and changes into particles. For exams, treat it as the beginning of dust and small bodies.

Correct answer: D. Hot and continuously changing

Early Earth was hot and later cooled to form layers. In exams, remember Earth's gradual evolution.