Class 12th

According to relation between field and potential, we can write

$\overrightarrow{E}=-\frac{dV}{dx}\left(\widehat{i}\right)=-\frac{d\left(3x^2\right)}{dx}\left(\widehat{i}\right)=-6x\left(\widehat{i}\right)$

${\overrightarrow{E}}_{\left(1,0,3\right)}=-6\left(\widehat{i}\right)N/C$

Let PT perpendicular to QR

$\frac{x+1}{2}=\frac{y+2}{3}=\frac{z-1}{2}=\lambda \Rightarrow T\left(2\lambda -1,3\lambda -2,2\lambda +1\right)$ therefore

$2\left(2\lambda -5\right)+3\left(3\lambda -4\right)+2\left(2\lambda -6\right)=0\Rightarrow \lambda =2$

$T\left(3,4,5\right)\therefore PT=\sqrt[]{1+4+4}=3\therefore QT=\sqrt[]{26-9}=\sqrt[]{17}$

$\therefore \Delta PQR=\frac{1}{2}*2\sqrt[]{17}*3=3\sqrt[]{17}$  

Therefore square of  $ar\left(\Delta PQR\right)$ = 153.

According to Lorentz's Force, we can write

$\overrightarrow{F}={\overrightarrow{F}}_{Electric}+{\overrightarrow{F}}_{Magnetic}=q\overrightarrow{E}+q\left(\overrightarrow{v}*\overrightarrow{B}\right),so$  

Statement I is correct but Statement II is incorrect

$f\text{'}\left(x\right)=\frac{4x^2-1}{x}$ so f (x) is decreasing in $\left(0,\frac{1}{2}\right)and\left(\frac{1}{2},\infty \right)$ $\Rightarrow a=\frac{1}{2}$  

Tangent at y² = 2x is y = mx + $\frac{1}{2m}$ it is passing through (4, 3) therefore we get m = $\frac{1}{2}or\frac{1}{4}$  

So tangent may be  $y=\frac{1}{2}x+1ory=\frac{1}{4}x+2buty=\frac{1}{2}x+1$  passes through (-2, 0) so rejected.

Equation of normal  $\frac{x}{9}+\frac{y}{36}=1$  

A salt bridge is a U-shaped tube that connects the two halves (oxidation and reduction) of the cell with an electrochemical cell, such as a galvanic cell. It allows the flow of ions in both halves and maintains the electricity to stay neutral.

${\displaystyle \underset{3}{\overset{x}{\int }}f\left(x\right)dx}={\left(\frac{f\left(x\right)}{x}\right)}^3\Rightarrow x^3{\displaystyle \underset{3}{\overset{x}{\int }}f\left(x\right)dx}=f^3\left(x\right),$ differentiating w.r.to x

$x^{3}f\left(x\right)+3x^2\frac{f^3\left(x\right)}{x^3}=3f^2\left(x\right)f\text{'}\left(x\right)\Rightarrow 3y^2\frac{dy}{dx}=x^{3}y=\frac{3y^3}{x}\Rightarrow 3xy\frac{dy}{dx}=x^4+3y^2$  

After solving we get  $y^2=\frac{x^4}{3}+c{x}^2$  also curve passes through (3, 3) Þ c = -2

$\therefore y^2=\frac{x^4}{3}-2x^2$ which passes through $\left(\alpha ,6\sqrt[]{10}\right)$ $\therefore \frac{{\alpha }^4-6{\alpha }^2}{3}=360\Rightarrow \alpha =6$  

In electrochemistry, metallic and electrolytic are two types of conductors.

The two branches of electrochemistry are: Electricity generated by chemical reactions and Chemical reactions that generate electricity.

${\displaystyle \underset{0}{\overset{1}{\int }}1.{\left(1-x^n\right)}^{2n+1}dx}$ using by parts we get

$\left(2n^2+n+1\right){\displaystyle \underset{0}{\overset{1}{\int }}{\left(1-x^n\right)}^{2n+1}dx=1177{\displaystyle \underset{0}{\overset{1}{\int }}{\left(1-x^n\right)}^{2n+1}dx}}$

$\Rightarrow 2n^2+n+1=1177\Rightarrow n=24or-\frac{49}{2}\therefore n=24$

According to question, we can write

$d=\sqrt[]{2hR}\Rightarrow \frac{d_2}{d_1}=\sqrt[]{\frac{h_2}{h_1}}\Rightarrow h_2={\left(\frac{d_2}{d_1}\right)}^2{h}_1={\left(\frac{2}{1}\right)}^2*125=500m$  

Increment in height of tower = h₂ – h₁ = 500 – 125 = 375 m