The acceleration of a moving body can be found from

Two identical current carrying coils with same centre are placed with their planes perpendicular to each other. If current $\mathrm{I}=\sqrt{2} \mathrm{~A}$ and radius of the coil is $R=1 \mathrm{~m}$, then magnetic field at centre is equal to ( $\mu_0=$ permeability of free space)

The frequency ' $v_{\mathrm{m}}$ ' corresponding to which the energy emitted by a black body is maximum may vary with the temperature ' $T$ ' of the body as shown by the curves ' A ', ' B ', ' C ' and ' D ' in the figure. Which one of these represents the correct variation?

The resistances in the left and right gap of a metre bridge are $40 \Omega$ and $60 \Omega$ respectively. When the bridge is balanced, the distance of the null point from the centre of the wire towards left is