\[ E = \frac{\Delta V}{d} \]
where \( \Delta V \) is the potential difference and \( d \) is the distance between the plates (0.02 m in this case).
\[ \Delta V = -70V - (-50V) = -20V \] \[ E_1 = \frac{20}{0.02} = 1000 \, V/m} \]
\[ \Delta V = 150V - (-50V) = 200V \] \[ E_2 = \frac{200}{0.02} = 10000 \, V/m} \]
\[ \Delta V = 200V - (-20V) = 220V \] \[ E_3 = \frac{220}{0.02} = 11000 \, V/m} \]
\[ \Delta V = -100V - (-400V) = 300V \] \[ E_4 = \frac{300}{0.02} = 15000 \, V/m} \]
Comparing the magnitudes:
\[ E_4>E_3>E_2>E_1 \]
Thus, the correct option is \( (C)} \, E_4>E_3>E_2>E_1 \).
.Match List-I with List-II.
Choose the correct answer from the options given below :}
There are three co-centric conducting spherical shells $A$, $B$ and $C$ of radii $a$, $b$ and $c$ respectively $(c>b>a)$ and they are charged with charges $q_1$, $q_2$ and $q_3$ respectively. The potentials of the spheres $A$, $B$ and $C$ respectively are:
Two resistors $2\,\Omega$ and $3\,\Omega$ are connected in the gaps of a bridge as shown in the figure. The null point is obtained with the contact of jockey at some point on wire $XY$. When an unknown resistor is connected in parallel with $3\,\Omega$ resistor, the null point is shifted by $22.5\,\text{cm}$ towards $Y$. The resistance of unknown resistor is ___ $\Omega$. 