Which of the following is used in photography?

If $\vec{a}, \vec{b}, \vec{c}$ are mutually perpendicular vectors having magnitudes $1, 2, 3$ respectively,then $[\vec{a}+\vec{b}+\vec{c} \quad \vec{b}-\vec{a} \quad \vec{c}]=$

$A$ uniform cube of side $a$ and mass $m$ rests on a rough horizontal table. $A$ horizontal force $F$ is applied normal to one of the faces at a point that is directly above the centre of the face,at a height $\frac{3a}{4}$ above the base. The minimum value of $F$ for which the cube begins to tilt about the edge is (Assume that the cube does not slide):

The same current is flowing in two alternating circuits. The first circuit contains only an inductor and the second contains only a capacitor. If the frequency of the $e.m.f.$ of the $ac$ source is increased,what will be the effect on the value of the current in these circuits?

For a telescope,the focal length of the objective lens is $15 \ cm$ and the focal length of the eyepiece is $10 \ mm$. If the tube length is $16 \ cm$,find the magnification.

The total charge induced in a conducting loop when it is moved in a magnetic field depends on