Answer : Option D) 
Explanation : When a positron is getting absorbed it means it will be
so, the
will get converted;
So, the whole reaction will be;
+
---->
.
This will convert the whole element of Cu will get changed into Zn. As, it absorbs by the positron, the atomic number gets increased from 29 to 30.
Answer:

Explanation:
= Mass of metal = 19 g
= Specific heat of the metal
= Temperature difference of the metal = 
V = Volume of water = 150 mL = 
= Density of water = 
= Specific heat of the water = 4.186 J/g°C
= Temperature difference of the water = 
Mass of water

Heat lost will be equal to the heat gained so we get

The specific heat of the metal is
.
Answer:c
Explanation:
softwood is used in doors roofs and so on
<span>fossil fuels are mainly organic compounds.Combustion of fossil fuels also produces other air pollutants, such as nitrogen oxides, sulfur dioxide, volatile organic compounds and heavy metals.so,substances which contain sulphur cause to form harmful acids like sulphuric and sulphurus acids</span>
Both indicate the temperature at which the solid and liquid states of a substance are in equilibrium would be your answer.
This is beacause the melting point of a substance is the same as the freezing point of a substance. At this particular temp, the substance can be either a solid or a liquid.
hope this helps!