Given data:
* The extension of the steel wire is 0.3 mm.
* The length of the wire is 4 m.
* The area of cross section of wire is,

* The young modulus of the steel is,

Solution:
The young modulus of the steel in terms of the force and extension is,

where F is the force acting on the steel wire,, l is the original length of the wire, dl is the extension of the wire, and A is the area,
Substituting the known values,

Thus, the force which produce the extension of 0.3 mm of the steel wire is 31.5 N.
It shows the ray passing through the boundary.
Answer:
-Radio waves
-Microwaves
-Infrared light (IR)
-Visible light
-Ultraviolet (UV)
-X-ray
-Gamma rays
(this is in order from the longest wavelength to shortest wavelength)
Answer:
All these particles behaves like small magnets which is known as domains
Explanation:
As we know that iron is a ferromagnetic substance so in this type of ferromagnetic substance all the medium particles will behave like small magnets which is known as small domains.
These domains have their own magnetic field which is very weak but if all the domains will align in same direction then all domains will combined and give strong magnetic field.
So in general case when iron nail is placed at room temperature then all these domains are randomly arranged and they do not give any net magnetic field while if we place the iron nail in external magnetic field then in that case the domains will align itself and give strong magnetic field in the direction of external field.
This is known as magnetization
Answer:
- 2.425 x 10^5 J
Explanation:
The gravitational potential energy between earth and the bock is given by

Where, G is the universal gravitational constant = 6.67 x 10^-11 Nm^2/kg^2
M is the mass of earth = 5.8 x 10^24 kg
m is the mass of block = 4 kg
r be the radius of earth = 6380 km = 6380 x 10^3 m
by substituting the values in the above expression, we get

U = - 2.425 x 10^5 J