| Direction: Q.1 to Q.5 |
| Current loop behaves like a magnetic dipole and has a magnetic field. They behave just like a magnet. Interesting part is, it depends upon the direction of current in loop which decides whether magnetic field line is in outward or inward direction. With the help of this outward and inward direction of magnetic field, north and south poles get decided. |
 |
 |
| Anticlockwise direction of current creates north pole (outward direction magnetic field) and clockwise direction of current creates a south pole (inward direction magnetic field). Magnetic dipole moment \[\overrightarrow{\text{M}}\] with the circular current loop carrying a current I and of area A. The magnitude of m is given by |
| \[|\overrightarrow{M}|=I\times A\] |
| Current in the circular coil produces magnetic field and Amperes found out that magnetic field created due to circular coil is similar to the magnetic field due to a bar magnet. Wood screw head sign shows that direction of screw is inward because we are not able to see pointed part of screw and so direction is inward. This inward direction of screw denotes the direction of the magnetic field. |
| Read the given passage carefully and give answer of the following questions: |
A) \[\frac{4}{{{\pi }^{2}}}M\]
B) M
C) \[\frac{4}{\pi }M\]
D) \[\frac{\pi }{4}M\]
Correct Answer: D
Solution :
(d) \[\frac{\pi }{4}M\] \[2\pi r=4l\] \[\Rightarrow l=\frac{\pi r}{2}[\because \,M\propto l]\] \[\Rightarrow \frac{M'}{M}=\frac{l\cdot \frac{{{\pi }^{2}}{{r}^{2}}}{4}}{l\cdot \pi {{r}^{2}}}=\frac{\pi }{4}\] \[\Rightarrow M'=\frac{\pi }{4}M\]
You need to login to perform this action.
You will be redirected in
3 sec
