Question of Exercise 2 (True and False)

Some natural phenomenon of Class 8

Question
Thunderstorms often occur at the end of cold, sticky winter days.

Frequently Asked Questions

Which is the nearest planet to the Sun

A: Venus

B: Jupiter

C: Mercury

D: Mars

 

Solution:

Explanation

  • Mercury is the planet that is closest to the Sun.
  • Then comes Venus, which is the second closest planet to the Sun, then Earth, which is the third closest planet to the Sun.
  • Mercury's distance from the Sun ranges from 46 million km to 69.8 million km.
  • The planet was most likely given its name because it travels so fast across space.
  • Mercury's temperature changes are the most dramatic in the solar system, ranging from 90 K to 700 K.
  • After Earth, Mercury is the densest significant planet in the solar system.

Final Answer

The correct option is C i.e Mercury.

 

Why do we need a Standard Meridian for India

Solution:

Explanation
  • Standard Meridian is a meridian which is  used to determine standard time.
  • The time of a place depends on the longitude that passes through it. Therefore, the standard time for each country is usually taken as the time of the central meridian that passes through it
  • India has a vast longitudinal extent. Since many meridians pass through india, 
  • Then it is important to adopt the local time of one central meridian of a country as the standard time for the country. 
  • Thus, we need a standard meridian for India.
Final Answer
  • We need a standard meridian for India because to adopt the local time of one central meridian of a country as the standard time for the country.
 

The smallest planet in the solar system is

A: Mars

B: Jupiter

C: Mercury

D: Earth

 

Solution:

Explanation:

There are several methods for determining how "large" something is.

  1.  The first is the mass of a thing (how much matter it contains), 
  2.  and the second is its volume (how much space it takes up). 

Mercury is the smallest planet in terms of both mass and volume, with a diameter of 4,879 km and a mass 3.3010×1023 of kg.

It is approximately 20 times less heavy than Earth, and its diameter is roughly 212 times smaller. In fact, Mercury is closer in size to our Moon than to Earth.

Final answer:

Hence, the correct option is (C)i.e mercury.

 

The sun rises two hours earlier in Arunachal Pradesh as compared to Gujarat in the west

But the clocks show the same time. How does this happen

Solution:

Explanation:

The sun rises two hours earlier in Arunachal Pradesh as compared to Gujarat in the west. But the clocks show the same time this happens because: 

i) The longitudinal gap between Arunachal Pradesh and Gujarat is about 30. 

ii) Due to this, there is time lag of about two hours between these states. 

iii) Since Arunachal Pradesh is in the east, the sun rises earlier here compared to Gujarat. 

iv) The Indian Standard Time is taken from the time of Standard Meridian of India and hence, the watches show the same time in both the states.

Final Answer:

As the longitudinal gap between Arunachal Pradesh and Gujarat is about 30 degrees, the time lag between these two states is two hours. Since Arunachal Pradesh is situated in the east, the sun rises earlier here compared to Gujarat in the west. But the watch shows the same time because of the Standard Meridian of India.

Define the following Threshold frequency and work function

Solution:

Answer:
 
Explanation:
 
The threshold frequency is the minimum frequency below which no photons are emitted.
 
The amount of least energy which is required to emit an electron from the surface is called the work function.
 
Final answer:
 
The threshold frequency is the minimum frequency below which no photons are emitted.
 
The amount of least energy which is required to emit an electron from the surface is called the work function.
 

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