Question
Surface area is

Answer

(a) $\phi = \overrightarrow B .\overrightarrow A $. In this formula $\overrightarrow A $ is a area vector.

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Similar questions

$100\,mA$ current gives a full scale deflection in a galvanometer of $2\,\Omega $ resistance. The resistance connected with the galvanometer to convert it into a voltmeter to measure $5\,V$ is ............... $\Omega $
Two sound waves of wavelength ${\lambda _1}$ and ${\lambda _2}$ $\left( {{\lambda _2} > {\lambda _1}} \right)$ produce $n\, beats/s$, the speed of sound is
A satellite moves around the earth in a circular orbit of radius $r$ with speed $v$. If the mass of the satellite is $M$, its total energy is
A block of mass $m$ lying on a rough horizontal plane is acted upon by a horizontal force $P$ and another force $Q$ inclined at an angle $\theta $ to the vertical. The block will remain in equilibrium, if the coefficient of friction between it and the surface is
Given below are two statements: One is labelled as Assertion $(A)$ and other is labelled as Reason $(R)$.

Assertion $(A)$ : Time period of oscillation of a liquid drop depends on surface tension $(S)$, if density of the liquid is $p$ and radius of the drop is $r$, then $T = k \sqrt{ pr ^{3} / s ^{3 / 2}}$ is dimensionally correct, where $K$ is dimensionless.

Reason $(R)$: Using dimensional analysis we get $R.H.S.$ having different dimension than that of time period.

In the light of above statements, choose the correct answer from the options given below.

An electric dipole is formed by two equal and opposite charges $q$ with separation $d$. The charges the same mass $m$. It is kept in a uniform electric field $E$. If it slightly rotated from its equilibrium orientation, then its angular frequency $\omega $ is
Consider earth to be a homogeneous sphere. Scientist $A$ goes deep down in a mine and scientist $B$ goes high up in a balloon. The value of $g$ measured by
A rod of length $l$ having uniformly distributed charge $Q$ is rotated about one end with constant frequency $'f'.$ Its magnetic moment
A sound wave of frequency $245 \,Hz$ travels with the speed of $300\, ms ^{-1}$ along the positive $x$-axis. Each point of the wave moves to and fro through a total distance of $6 \,cm$. What will be the mathematical expression of this travelling wave ?
A $100 \,\Omega$ resistance, a $0.1\, \mu {F}$ capacitor and an inductor are connected in series across a $250 \,{V}$ supply at variable frequeny. Calculate the value of inductance of inductor at which resonance will occur. Given that the resonant frequency is $60\, {Hz}$. (In ${H}$)