The magnetic field at the centre of a circular coil of radius ' \(R\) ', carrying current \(2 \mathrm{~A}\) is ' \(\mathrm{B}_1\) '. The magnetic field at the centre of another coil of radius ' \(3 R\) ' carrying current \(4 A\) is ' \(B_2\) '. The ratio \(B_1: B_2\) is

The majority charge carriers in p-type and n-type semiconductor are respectively

If two light waves reaching at a point produce destructive interference, then condition of phase difference is

The displacement of a wave travelling in the \(\mathrm{x}\) direction is \(\mathrm{y}=10^{-4} \sin [600 \mathrm{t}-2 \mathrm{x}+\pi / 3] \mathrm{m}\), where \(\mathrm{x}\) is in metre and \(\mathrm{t}\) in second. The speed of the wave is

The radii of curvature of both the surface of a convex lens of focal length ' \(\mathrm{f}\) ' and focal power ' \(\mathrm{P}\) ' are equal. One of the surfaces is made plane by grinding. The new focal length and focal power of the lens is respectively

A thin metal wire of length ‘ $L$ ’ and uniform linear mass density ‘ $Q$ ’ is bent into a circular coil with ‘ $O$ ’ as centre. The moment of inertia of a coil about the axis $XX\text{'}$ is

In moving coil galvanometer, strong horse shoe magnet of concave shaped pole pieces is used to

Which among the following is NOT obtained when bromobenzene treated with bromoethane and sodium in presence of dry ether?

Which of the following function is not continuous at $x=0?$

If \(\overline{\mathrm{a}}, \overline{\mathrm{b}}, \overline{\mathrm{c}}\) are non-coplanar vectors and \(\overline{\mathrm{p}}=\frac{\overline{\mathrm{b}} \times \overline{\mathrm{c}}}{[\overline{\mathrm{a}} \overline{\mathrm{b}} \overline{\mathrm{c}}]}, \overline{\mathrm{q}}=\frac{\overline{\mathrm{c}} \times \overline{\mathrm{a}}}{[\overline{\mathrm{a}} \overline{\mathrm{b}} \overline{\mathrm{c}}]}, \overline{\mathrm{r}}=\frac{\overline{\mathrm{a}} \times \overline{\mathrm{b}}}{[\overline{\mathrm{a}} \overline{\mathrm{b}} \overline{\mathrm{c}}]}, \quad\) then \(2 \overline{\mathrm{a}} \cdot \overline{\mathrm{p}}+\overline{\mathrm{b}} \cdot \overline{\mathrm{q}}+\overline{\mathrm{c}} \cdot \overline{\mathrm{r}}=\)

A body is projected from earth's with thrice the escape velocity from the surface of the earth. What will be its velocity when it will escape the gravitational pull?

If \(\mathrm{f}(x)=\left(\frac{1+\tan x}{1+\sin x}\right)^{\operatorname{cosec} x}\) is continuous at \(x=0\), then \(f(0)\) is equal to

The initial step in preparation of beer is