Class 12th

There are two types of electricity - Static and Current electricity. The electric charges buildup on a material's surface is called the static electricity. The continuous flow of electric charge is termed as the current electricity. Current electricity is of two types - Alternating Current (AC) and Direct Current (DC). In AC, the charge direction reverses periodically and in DC, charge flows in one direction.

According to Einstein's photoelectric equation maximum kinetic energy of photoelectrons, $K{E}_{ max }=E_v-\phi$

or   $2=5-\phi$ $\therefore \phi =3eV$

When $E_v=6eV$  then, $K{E}_{ max }=6-3=3eV$

or $e\left(V_{cathode}-V_{anode}\right)=3eV$

or   $V_{cathode}-V_{anode}=3V=-V_{stopping}$

  $\therefore V_{stopping}=-3V$

Kindly consider the following figure

The current's SI unit is ampere. The symbol for ampere is A. The term ampere is named after the French physicist André-Marie Ampère.

Mixture of acetone and chloroform shows negative deviation from Raoult's law because of hydrogen bonding

In simple words, current electricity can be defined as the electric charge continuously moving from one place to another along a pathway. It is measured in amperes (A). Electric current is needed for electrical devices to work.

From work energy theorem

$W_{sp}+W_E=?K$

$-\frac{1}{2}k{x}_0^2+QE.x_0=0$

$?x_0=\frac{2QE}{k}$

$t_{99.9}=\frac{2.303}{k}\log ?\frac{100}{100-99.9}=3*\frac{2.303}{k}$

$t_{50}=\frac{0.693}{k}$

$\frac{t_{99.9}}{t_{50}}=\frac{3*2.303*k}{k*0.693}=\frac{9}{96}\approx 10$

Optimum pH range for enzymatic activity is 5 to 7

No, in fact, it is one of the easiest chapter of class 12 Physics. Other chapters which are considered comparatively easy are Ray Optics and Electric Charges and Fields.