At a certain place the angle of dip is 30° and the horizontal component of earth’s magnetic field is 0.5 G. The earth’s total magnetic field (in G), at that certain place, is
- \(\frac{1}{\sqrt3}\)
- \(\frac{1}{2}\)
- \(\sqrt3\)
- 1
The Correct Option is A
Solution and Explanation
The correct option is(A): \(\frac{1}{\sqrt3}\)
BH = Bcos30°
\(⇒B=\frac{1}{\sqrt3}G\)
Top JEE Main Physics Questions
- In a hydrogen like atom, when an electron jumps from the $M$ - shell to the $L$ - shell, the wavelength of emitted radiation is $\lambda$. If an electron jumps from $N$-shell to the $L$-shell, the wavelength of emitted radiation will be :
- Two masses $m$ and $\frac{m}{2}$ are connected at the two ends of a massless rigid rod of length $l$. The rod is suspended by a thin wire of torsional constant $k$ at the centre of mass of the rod-mass system(see figure). Because of torsional constant $k$, the restoring torque is $\tau =k\theta$ for angular displacement $\theta$. If the rod is rota ted by $\theta_0$ and released, the tension in it when it passes through its mean position will be:
A black body is at a temperature of 2880 K. The energy of radiation emitted by this body with wavelength between 499 nm and 500 nm is U1, between 999 nm and 1000 nm is U2 and between 1499 nm and 1500 nm is U3. The Wien's constant, b = 2.88×106 nm-K. Then,
- $I _{ CM }$ is the moment of inertia of a circular disc about an axis (CM) passing through its center and perpendicular to the plane of disc $I_{A B}$ is it's moment of inertia about an axis $AB$ perpendicular to plane and parallel to axis $CM$ at a distance $\frac{2}{3} R$ from center Where $R$ is the radius of the dise The ratio of $I _{ AB }$ and $I _{ CM }$ is $x: 9$ The value of $x$ is______
- A nucleus disintegrates into two smaller parts, which have their velocities in the ratio $3: 2$ The ratio of their nuclear sizes will be $\left(\frac{x}{3}\right)^{\frac{1}{3}}$ The value of ' $x$ ' is:-
Top JEE Main Magnetic Field Questions
- Consider a rod moving in a magnetic field as shown:
The induced emf across the ends of the rod is The magnetic flux through a loop varies with time as \(Φ= 5t^2 -3t +5\). If the resistance of loop is \(8\) , find the current through it at \(t = 2\) \(s\)
- Two rings of equal radius \(R\) arranged perpendicular to each other with common center at \(C\), carrying equal current \(I\). Find magnetic field at \(C\).
- A long wire carrying current \(\sqrt{(2)}A\) is placed in a uniform magnetic field of \(3 \times 10^{-5}\; T\). If the magnetic field is perpendicular to wire, find magnetic force on the length of wire.
- The electric field in an electromagnetic wave is moving in a free space given as vec \(E =E_ 0 \;sin(⍵t - kz)\) \(i\) The corresponding magnetic field will be:
Top JEE Main Questions
- In a hydrogen like atom, when an electron jumps from the $M$ - shell to the $L$ - shell, the wavelength of emitted radiation is $\lambda$. If an electron jumps from $N$-shell to the $L$-shell, the wavelength of emitted radiation will be :
- Two masses $m$ and $\frac{m}{2}$ are connected at the two ends of a massless rigid rod of length $l$. The rod is suspended by a thin wire of torsional constant $k$ at the centre of mass of the rod-mass system(see figure). Because of torsional constant $k$, the restoring torque is $\tau =k\theta$ for angular displacement $\theta$. If the rod is rota ted by $\theta_0$ and released, the tension in it when it passes through its mean position will be:
What will be the equilibrium constant of the given reaction carried out in a \(5 \,L\) vessel and having equilibrium amounts of \(A_2\) and \(A\) as \(0.5\) mole and \(2 \times 10^{-6}\) mole respectively?
The reaction : \(A_2 \rightleftharpoons 2A\)- The value of is
- The number of terms of an is even. The sum of the odd terms is and of the even terms is . The last term exceeds the first by . Then the number of terms in the series is ______.
Concepts Used:
Earth’s Magnetic field
The Earth's magnetic field stretches millions of kilometers into space and resembles a bar magnet. The earth's magnetic pole is positioned between the Northern Pole and the North Pole's Antarctic magnets. That is why a compass magnet's north pole points north (north and south poles attract).
The Earth's magnetic field extends far and wide, but it is very small in terms of field power. It has a field power of merely 40,000 nT as compared to a refrigerator magnet which has a power of 107 nT.
Theory of Earth’s Magnetism
- The Dynamo Effect: The outer core of the earth has molten Iron and other heavy elements in liquid form. The inner core solidifies under the influence of gravity. Therefore, the motion of metallic fluids in the outer core of the earth causes an electric current. Thus, the earth gets its own magnetic field lines.
- Ionization of the Outer Layers: This theory tells us that the rotation of the earth in its own axis produces strong electric current due to the ionization of the outer layers of earth. This produces magnetism due to the movement of the ions. However, the magnetic field will be very weak. The Dynamo Effect is the more acceptable theory.
Components of Earth’s Magnetic Field
These are the components that are responsible for the magnitude and direction of the magnetic field of the earth at a given location:
- Magnetic Declination
- Horizontal Component of Earth’s Magnetic Field
- The angle of Dip or Magnetic Inclination