Answer:
208.7°C was the initial temperature of the limestone.
Explanation:
Heat lost by limestone will be equal to heat gained by the water

Mass of limestone = 
Specific heat capacity of limestone = 
Initial temperature of the limestone = 
Final temperature =
=T = 51.9°C

Mass of water= 
Specific heat capacity of water= 
Initial temperature of the water = 
Final temperature of water =
=T = 51.9°C



On substituting all values:


208.7°C was the initial temperature of the limestone.
Ozone which is present in the stratospheric region of atmosphere is helpful for preventing harmful UV rays from reaching the surface of earth. Due to human activity, several compounds (specifically chlorofluorocarbons) are released in atmosphere. Due to inherent chemical stability of these compounds, the remain stable in lower region of atmosphere and slowly diffuse into stratosphere. On reaching the stratosphere, these compounds reacts with ozone and thereby depletes the effective concentration of ozone present in atmosphere. Hence, <span>the Montreal Protocol was signed in 1987 by major countries of the world. This aim of this protocol was to protect the stratospheric ozone layer by phasing out the production and consumption of ozone-depleting substances.</span>
Answer:
The temperature associated with this radiation is 0.014K.
Explanation:
If we assume that the astronomical object behaves as a black body, the relation between its <em>wavelength</em> and <em>temperature</em> is given by Wien's displacement law.

where,
λmax is the wavelength at the peak of emission
b is Wien's displacement constant (2.89×10⁻³ m⋅K)
T is the absolute temperature
For a wavelength of 21 cm,

You would get 35.................
Endothermic reaction is the reaction in which the system absorbs energy. The system absorbs heat and cools the surroundings. Reactants are the substances that are involved in the reaction and at the end of the reaction product are formed.
In the endothermic reaction because heat is absorbed , the products have a higher heat.