Astrophysics 1

What are artificial satellites used for?

• Observing wildlife

• Satellite imaging and communications

• Monitoring seismic activity

• Deep-sea exploration

Answer explanation

Artificial satellites are primarily used for satellite imaging and communications, enabling global communication, data transmission, and Earth observation. Other options like wildlife observation and deep-sea exploration are not typical satellite functions.

What does the Big Bang Theory suggest about the universe?

• It is shrinking

• It is static

• It has expanded from a very small, hot, and dense point

• It is heating up

Answer explanation

The Big Bang Theory posits that the universe has expanded from an extremely small, hot, and dense state. This expansion is a fundamental aspect of the theory, distinguishing it from ideas of a static or shrinking universe.

What is the nature of circular orbits?

• They are elliptical

• They have constant velocity

• Gravity provides the required force

• They are square-shaped

Answer explanation

Circular orbits are maintained by the force of gravity, which provides the necessary centripetal force to keep an object in motion along a circular path. This is why the correct answer is 'Gravity provides the required force'.

What are comets made of?

• Gas and plasma

• Rock, dust, and ice

• Metal and liquid

• Sand and water

Answer explanation

Comets are primarily composed of rock, dust, and ice, which form a solid nucleus. When they approach the Sun, the heat causes the ice to vaporize, creating a glowing coma and tail, distinguishing them from other celestial bodies.

What does the Doppler Effect describe?

• Change in temperature

• Change in a wave’s observed wavelength and frequency

• Change in light intensity

• Change in gravitational pull

Answer explanation

The Doppler Effect describes how the observed wavelength and frequency of a wave change due to the relative motion between the source and the observer, making 'Change in a wave’s observed wavelength and frequency' the correct choice.

What does the Hertzsprung-Russell Diagram plot?

• The speed of stars

• The luminosity of stars against their temperatures

• The distance of stars from Earth

• The age of stars

Answer explanation

The Hertzsprung-Russell Diagram plots the luminosity of stars against their temperatures, allowing astronomers to classify stars and understand their evolutionary stages.

Where is the Milky Way Galaxy located?

• In another universe

• In a distant galaxy

• It is the galaxy where our solar system is located

• In a black hole

Answer explanation

The Milky Way Galaxy is the galaxy that contains our solar system, making the correct answer "It is the galaxy where our solar system is located." The other options incorrectly suggest locations outside our galaxy.

What are natural satellites?

• Man-made satellites

• The moons that orbit planets

• Stars that orbit planets

• Comets that orbit planets

Answer explanation

Natural satellites are defined as the moons that orbit planets. They are not man-made, stars, or comets, making 'the moons that orbit planets' the correct choice.

What is the radius of a body's orbit called?

• Orbital Speed

• Orbital Period

• Orbital Radius

• Red-Shift

Answer explanation

The radius of a body's orbit is referred to as the 'Orbital Radius'. It defines the distance from the center of the orbiting body to the center of the body it orbits, distinguishing it from other terms like speed or period.

What measures how fast an object orbits?

• Orbital Radius

• Orbital Speed

• Orbital Period

• Star Life Cycle

Answer explanation

Orbital speed measures how fast an object travels along its orbit. It is determined by the distance covered in a given time, making it the correct choice for measuring the speed of an orbiting object.