Level 1

Two long wires each carrying a $DC$ current in the same direction are placed close to each other. Which one of the following statements is correct?

The mean radius of a toroid is $10 \mathrm{cm}$ and number of turns are $500$. If current flowing through it is $0.1$ ampere. The value of magnetic field (in Tesla) for toroid is ${10}^{-\mathrm{x}}$. Then, the value of $x$ is:-

When the number of turns in a toroidal coil is doubled, then the value of magnetic flux density will becomes

At a place, the horizontal and vertical components of the Earth's magnetic field are equal. Find the angle (in degree) of dip at that place.

The soft iron (used as core material) has,

What is the magnitude of the torque in $\mathrm{N} \mathrm{m}$ acting on a solenoid which has a magnetic moment of $0.65\mathrm{ }\mathrm{J}\mathrm{ }{\mathrm{T}}^{-1}$ when its axis makes an angle of $30°$ with the direction of the applied uniform horizontal magnetic field of $0.25\mathrm{ }\mathrm{T}$?

Find the maximum torque of a loop with magnetic moment $12.5$ and flux density $4$ units.

For a paramagnetic material, magnetic susceptibility changes with temperature of material. Suppose for a paramagnetic material susceptibility at $100 °\mathrm{C}$ is $353\times {10}^{-6}$. Find its susceptibility (in multiple of ${10}^{-6}$) at $80 °\mathrm{C}$