Double Displacement Reaction
An element from each of two compounds switch places.
Example: compound + compound ⇒ compound + compound
Chemical reactions are processes in which substances change into other substances. A chemical reaction takes place if one or more of these occur:
Color changes - Different combinations of molecules reflect light differently. A color change indicates a change in molecules.
Heat content changes- In all chemical reactions, the heat content of the reactants and the heat content of the products is never the same. Sometimes the difference is great and can be easily detected. At other times, the difference is slight and more difficult to detect.
Gas produced - Whenever a gaseous product forms in a liquid solution, bubbles can be seen. A colorless gas produced in a reaction of solids is much harder to detect.
Precipitate forms- Precipitates are insoluble products formed by a reaction taking place in a liquid solution. This insoluble product will eventually settle to the bottom, but might immediately appear by turning the clear solution cloudy.
Answer:
From -15⁰ to 0⁰
H=mc¶
where H= heat absorbed or evolved
m=mass involved
c=specific heat capacity
¶=change in temperature
H=mc¶
Answer:
The mass of the another block is 60 kg.
Explanation:
Given that,
Mass of block M= 100 kg
Height = 1.0 m
Time = 0.90 s
Let the mass of the other block is m.
We need to calculate the acceleration of each block
Using equation of motion

Put the value into the formula



We need to calculate the mass of the other block
Using newton's second law
The net force of the block M

....(I)
The net force of the block m

Put the value of T from equation (I)



Put the value into the formula


Hence, The mass of the another block is 60 kg.
Answer:
Final Length = 30 cm
Explanation:
The relationship between the force applied on a string and its stretching length, within the elastic limit, is given by Hooke's Law:
F = kΔx
where,
F = Force applied
k = spring constant
Δx = change in length of spring
First, we find the spring constant of the spring. For this purpose, we have the following data:
F = 50 N
Δx = change in length = 25 cm - 20 cm = 5 cm = 0.05 m
Therefore,
50 N = k(0.05 m)
k = 50 N/0.05 m
k = 1000 N/m
Now, we find the change in its length for F = 100 N:
100 N = (1000 N/m)Δx
Δx = (100 N)/(1000 N/m)
Δx = 0.1 m = 10 cm
but,
Δx = Final Length - Initial Length
10 cm = Final Length - 20 cm
Final Length = 10 cm + 20 cm
<u>Final Length = 30 cm</u>
Answer:
b.
Explanation:
In case of Single Slit, diffraction will occur.
Then In Single slit Diffraction, width of central fringe is

where D= distance b/w screen and slit
a= slit width
\lambda = wavelength
Thus if Screen width increases keeping other factors same then width of central fringe becomes narrower as

On increasing the slit width the central bright fringe width The width of the central bright fringe becomes narrower.