Tag: solar system and sun

Questions Related to solar system and sun

Earth is revolving around the sun.If the distance of earth from the sun is reduced to $\frac { 1 } { 4 } \mathrm { th }$ of the present distance, then the length of present day will be reduced by 

  1. 1 / 4

  2. 1 / 2

  3. 1 / 8

  4. 1 / 6


Correct Option: A

The mass of a planet Jupiter is $1.9 \times 10^{27} kg$ and that of the Sun is $1.99 \times 10^{30} kg$. The mean distance of the Sun from Jupiter is $7.8 \times 10^{11} m$. The gravitational force, which the Sun exerts on Jupiter is.

  1. $4.1 \times 10^{23} N$

  2. $4.1 \times 10^{34} N$

  3. $2.2 \times 10^{23} N$

  4. $2.2 \times 10^{34} N$


Correct Option: A

Two plates move around the Sun. The periodic times and the mean radii of the orbits are $T _1, T _2$ and $r _1, r _2$ respectively. The ratio $\dfrac{T _1}{T _2}$ is equal to.

  1. $\left (\dfrac{r _1}{r _2} \right)^{\dfrac{1}{2}}$

  2. $\left (\dfrac{r _1}{r _2} \right)$

  3. $\left (\dfrac{r _1}{r _2} \right)^{2}$

  4. $\left (\dfrac{r _1}{r _2} \right)^{\dfrac{3}{2}}$


Correct Option: D

As per modern classification of solar system, number of planets excluding Earth is: 

  1. $7$

  2. $8$

  3. $9$

  4. $10$


Correct Option: A
Explanation:
As per older convention, there used to be $9$ planets in total in the solar system. As per modern convention, Pluto is no more a planet. So, excluding Earth, there are $7$ planets in total.

The radius of Jupiter is 11 times the radius of the Earth. Calculate the ratio of the volumes of Jupiter and the Earth. How many Earths can Jupiter accommodate ? 

  1. 1331

  2. 1221

  3. 111

  4. None of these


Correct Option: A
Explanation:

Planets are like spheres. Volume of a sphere is given by, 
V = $\displaystyle{\frac{4}{3}\pi r^3}$ 
Let the r$ _1$, r$ _2$ be radii of the Jupiter and the Earth respectively. 
r$ _1$ $= 11r _2$ _(1)
Volume of Jupiter, V$ _1$ = $\displaystyle{\frac{4}{3}\pi r^3 _1}$ _(2) 
Volume of Earth, V$ _2$ = $\displaystyle{\frac{4}{3}\pi r^3 _2}$ _(3) 
$\displaystyle{\frac{(2)}{(3)} \Rightarrow \frac{V _1}{V _2} = \frac{\frac{4}{3}\pi r _1^3}{\frac{4}{3} \pi r _2^3} = \frac{r _1^3}{r _2^3}}$ 
$\displaystyle{\frac{V _1}{V _2} = \frac{r _1^3}{r _2^3} = \frac{(11r _2)^3}{r _2^3} = (11)^3}$ = 1331 
Jupiter can accommodate 1331 number of Earths within it.

The earth spins about its axis from

  1. west to east

  2. east to west

  3. north to south

  4. south to north


Correct Option: A
Explanation:

Earth spins about its own axis from west to east. In another word earth turns counter clockwise direction as viewed from north pole.

The mean distance between Earth and Sun is referred to as one

  1. light year

  2. fermi

  3. astronomical unit

  4. angstrom


Correct Option: C
Explanation:

On Astronomical unit is the mean distance between earth and sun.

Days and nights are caused by

  1. rotation of the Earth

  2. revolution of the Earth

  3. both rotation and revolution of the Earth

  4. neither rotation nor revolution of the Earth


Correct Option: A
Explanation:

As earth is rotating on its own axis so its half part is exposed to sun cause day at that part and hidden half part suffers from darkness called night.

All the stars appear to move from

  1. west to east

  2. east to west

  3. north to south

  4. south to north


Correct Option: B
Explanation:

As earth is rotating on its own axis from west to east so, due to relative motion star appears to move from east to west.

The planet which shows retrograde motion is

  1. Venus

  2. Mercury

  3. Jupiter

  4. Mars


Correct Option: A
Explanation:

Ans : Venus