Tag: universe and space

Questions Related to universe and space

The Hubble Space Telescope is designed with ____________  hyperbolic mirrors is known for good imaging performance over a wide field of view. 

physics universe and space xx radio telescope and space telescopes optical instruments : telescope

  1. two

  2. four

  3. three

  4. many

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Correct Option: A
Explanation:

Hubble space telescope is reflecting telescope it is designed with TWO hyperbolic mirrors. A curved primary mirror is the basic optical element that creates an image at the focal plane. And secondary mirror was added to modify the optical characteristics for visual observation.

Which among the following is not true for Hubble ST?

physics universe and space xx radio telescope and space telescopes optical instruments : telescope

  1. Hubbles observations found that black holes are common to the centers of all galaxies.

  2. Hubble's Telescope was first to found the traces of water on Earth.

  3. Hubble Deep field and Hubble Ultra Deep Field images reveal galaxies that are billions of light-years away.

  4. Astronauts used the telescope to observe distant supernovae.

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Correct Option: B
Explanation:

We know that Earth has water, blue planet, 71% of Earth's surface is covered in water. Hubble telescope was definitely not the first to found the traces of water on Earth. 

What is the range of gravitational force. ?

physics universe and space heliocentric model introduction to gravitation introduction to gravity

  1. $10^{-2}$m

  2. $10^{-15}$m

  3. infinite

  4. $10^{-10}$m

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Correct Option: C
Explanation:

The range of gravitational force is infinite.

Let $F _{1}$ be the magnitude of the gravitational force exerted on the Sun by Earth and $F _{2}$ be the magnitude of the force exerted on Earth by the Sun. Then.

physics universe and space heliocentric model introduction to gravitation introduction to gravity

  1. $F _{1}$ is much greater than $F _{2}$

  2. $F _{1}$ is slightly greater than $F _{2}$

  3. $F _{1}$ is equal to $F _{2}$

  4. $F _{1}$ is slightly less than $F _{2}$

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Correct Option: C

Value of $G$ is

physics universe and space heliocentric model introduction to gravitation introduction to gravity

  1. $6.675\times {10}^{11}{Nm}^{2}{kg}^{-2}$

  2. $6.675\times {10}^{10}{Nm}^{2}{kg}^{-2}$

  3. $6.675\times {10}^{-12}{Nm}^{2}{kg}^{-2}$

  4. $6.675\times {10}^{-11}{Nm}^{2}{kg}^{-2}$

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Correct Option: D

A block weights $5 N$ in air, $4.5 N$ in a liquid of specific gravity $0.5$ Its weight in water will be

physics universe and space heliocentric model introduction to gravitation introduction to gravity

  1. $3.5 N$

  2. $4.0 N$

  3. $2.5 N$

  4. $3.0 N$

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Correct Option: A

------------ is the force of attraction between any two bodies in the universe.

physics universe and space heliocentric model introduction to gravitation introduction to gravity

  1. Gravitation

  2. Polarity

  3. Induction

  4. Joule

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Correct Option: A
Explanation:

Any two objects attract each other with a force $F _g=\dfrac{GMm}{R^2}$ where $G$ is the gravitational constant, $M$ and $m$ the masses of the two bodies and $R$ is the distance along the line joining their centre of mass

State whether the given statement is True or False :

All objects attract each other along the line joining their centre of mass.

physics universe and space heliocentric model introduction to gravitation introduction to gravity

  1. True

  2. False

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Correct Option: A
Explanation:

Any two objects attract each other with a force $F _g=\dfrac{GMm}{R^2}$ where $G$ is the gravitational constant, $M$ and $m$ the masses of the two bodies and $R$ is the distance along the line joining their centre of mass

The horizontal component of the weight of a body of mass $m$ is

physics universe and space heliocentric model introduction to gravitation introduction to gravity

  1. $mg$

  2. $\displaystyle \dfrac{\mathrm{m}\mathrm{g}}{2}$

  3. $0$

  4. Infinity

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Correct Option: C
Explanation:

The force of gravity is the force with which the earth, moon, or other massively large object attracts another object towards itself. By definition, this is the weight of the object. All objects upon earth experience a force of gravity that is directed "downward" towards the center of the earth. So, the horizontal component of the weight of body of mass $m$ will be $0$. $Option$ $C$ is correct.

An Earth's satellite is moving in a circular orbit with a uniform speed $v$. If the gravitational force of the Earth suddenly disappears, the satellite will

physics universe and space heliocentric model introduction to gravitation introduction to gravity

  1. vanish into outer space.

  2. continue to move with velocity $v$ in original orbit.

  3. fall down with increasing velocity.

  4. fly off tangentially from the orbit with velocity $v$.

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Correct Option: D
Explanation:

The satellite revolves around the Earth in a circular orbit when centrifugal force acting outward on the satellite is balanced by the gravitational force of the Earth. Thus, when gravitational force suddenly disappears, then only centrifugal force will be acting and velocity is tangential to the orbit and hence, the satellite will fly off tangentially. It is similar to an object tied with a string, fly off when string suddenly breaks.