The component of vector $\overrightarrow{A} = a_x \hat{i} + a_y \hat{j} + a_z \hat{k}$ along the direction of $\hat{i} - \hat{j}$ is

$A$ $2 \ m$ long rod of radius $1 \ cm$ which is fixed from one end is given a twist of $0.8 \ radians$. The shear strain developed will be

The equivalent resistance between $A$ and $B$ is

$\cos A \cos 2 A \cos 4 A \ldots \cos 2^{n-1} A$ equals

$A$ simple pendulum performs simple harmonic motion about $x=0$ with an amplitude '$a$' and time period '$T$'. The speed of the pendulum at $x=\frac{a}{2}$ is

For a crystal,the angle of diffraction $(2 \theta)$ is $90^{\circ}$ and the second order line has a $d$ value of $2.28 \ \mathring{A}$. The wavelength (in $\mathring{A}$) of $X$-rays used for Bragg's diffraction is