Exercise-1

Value of earth's magnetic field at any point is $7\times {10}^{-5} \mathrm{wb} {\mathrm{m}}^{-2}$. This field is neutralised by field which is produced at the centre of a current carrying loop of radius $5 \mathrm{cm}$. The current in the loop (approx)

A vertical straight conductor carries a current vertically upwards. A point $P$ lies to the east of it at a small distance and another point $Q$ lies to the west at the same distance. The magnetic field at $P$ is:

Using mass $\left(M\right)$, length $\left(L\right)$, time $\left(T\right)$ and current $\left(A\right)$ as fundamental quantities, the dimension of permeability is: 

Which physical quantity has dimensions $\left[M^1{L}^1{T}^{-2}{A}^{-2}\right]$:

Intensity of magnetic field of the earth at a point inside a hollow iron box is :

The relative permeability of air is: 

The value of earth magnetic field $B_H=0.3$ gauss. In this magnetic field a magnet is oscillating with $5$ oscillation/min. To increase the oscillation of magnet upto $10$ oscillation/min. The value of earth magnetic field increased by:

Tangent galvanometer is used to measure: