Scientists have been observing Earth for a long time. They use NASA satellites and other instruments to collect many types of information about Earth's land, atmosphere, ocean and ice. This information tells us that Earth's climate is getting warmer.
Extra:
Extra greenhouse gases in our atmosphere are the main reason that Earth is getting warmer. Greenhouse gases, such as carbon dioxide (CO2) and methane, trap the Sun's heat in Earth's atmosphere.
It's normal for there to be some greenhouse gases in our atmosphere. They help keep Earth warm enough to live on. But too many greenhouse gases can cause too much warming.
The burning of fossil fuels like coal and oil increase the amount of CO2 in our air. This happens because the burning process combines carbon with oxygen in the air to make CO2.
It's important that we monitor CO2 levels, because too much CO2 can cause too much warming on Earth. Several NASA missions have instruments that study CO2 in the atmosphere.
The magnitude of electric field is produced by the electrons at a certain distance.
E = kQ/r²
where:
E = electric field produced
Q = charge
r = distance
k = Coulomb Law constant 9 x10^9<span> N. m</span>2<span> / C</span><span>2
Given are the following:
Q = </span><span>1.602 × 10^–19 C
</span><span>r = 38 x 10^-9 m
Substitue the given:
E = </span>
E = 998.476 kN/C
Answer:
Mass of the aluminium chunk = 278.51 g
Explanation:
For an isolated system as given the energy lost and gains in the system will be zero therefore sum of all transfer of energy will be zero,as the temperature will also remain same
A specific heat formula is given as
Energy Change = Mass of liquid x Specific Heat Capacity x Change in temperature
Q = m×c×ΔT
Heat gain by aluminium + heat lost by copper = 0 (1)
For Aluminium:
Q = 
Q = m x 17.94 joule
For Copper:

Q= 4996.53 Joule
from eq 1
m x 17.94 = 4996.53

Mass of the aluminium chunk = 278.51 g
Answer:
Option (c) is correct.
Explanation:
The apparent change in the frequency of light due to the relative motion between the source and the observer is called Doppler's effect.
When the source is moving towards the observer which is at rest, the apparent frequency increases and if the observer is moving away the frequency of sound decreases.
It occurs for both light and sound.
So, to explain the blue shift of light in the universe is due to the Doppler's effect of light.