Four condensers each of capacitance 8 muF are joined as shown in the figure. The equivalent capacitance between the points A and B will be

32 μF
2 μF
8 μF
16 μF
We are given four capacitors, each of capacitance \( 8 \ \mu F \), connected as shown in the diagram. We need to calculate the equivalent capacitance between points A and B.
Step 1: Identifying the Capacitor Connections
From the figure: - The top two capacitors are in series. - The bottom two capacitors are also in series. - These two series combinations are in parallel with each other.
Step 2: Capacitance of Each Series Pair
The capacitance of two capacitors in series is given by: \[ \frac{1}{C_{\text{series}}} = \frac{1}{C} + \frac{1}{C} \] Since each capacitor has capacitance \( 8 \ \mu F \), \[ \frac{1}{C_{\text{series}}} = \frac{1}{8} + \frac{1}{8} = \frac{2}{8} = \frac{1}{4} \] Thus, \[ C_{\text{series}} = 4 \ \mu F \] Step 3: Equivalent Capacitance of Parallel Combination
The two series combinations are now in parallel. For capacitors in parallel: \[ C_{\text{eq}} = C_{\text{series}} + C_{\text{series}} \] \[ C_{\text{eq}} = 4 \ \mu F + 4 \ \mu F = 8 \ \mu F \]
Step 4: Final Equivalent Capacitance
Notice that this combination is in parallel with another identical combination of capacitors (from symmetry in the diagram). The total equivalent capacitance is: \[ C_{\text{total}} = 8 \ \mu F + 8 \ \mu F = 32 \ \mu F \]
Step 5: Final Answer
\[ \boxed{32 \ \mu F} \]
Match List - I with List - II:
List - I:
(A) Electric field inside (distance \( r > 0 \) from center) of a uniformly charged spherical shell with surface charge density \( \sigma \), and radius \( R \).
(B) Electric field at distance \( r > 0 \) from a uniformly charged infinite plane sheet with surface charge density \( \sigma \).
(C) Electric field outside (distance \( r > 0 \) from center) of a uniformly charged spherical shell with surface charge density \( \sigma \), and radius \( R \).
(D) Electric field between two oppositely charged infinite plane parallel sheets with uniform surface charge density \( \sigma \).
List - II:
(I) \( \frac{\sigma}{\epsilon_0} \)
(II) \( \frac{\sigma}{2\epsilon_0} \)
(III) 0
(IV) \( \frac{\sigma}{\epsilon_0 r^2} \) Choose the correct answer from the options given below:

Space between the plates of a parallel plate capacitor of plate area 4 cm$^2$ and separation of $ d = 1.77 \, \text{mm} $, is filled with uniform dielectric materials with dielectric constants (3 and 5) as shown in figure. Another capacitor of capacitance 7.5 pF is connected in parallel with it. The effective capacitance of this combination is ____ pF.
If the roots of $\sqrt{\frac{1 - y}{y}} + \sqrt{\frac{y}{1 - y}} = \frac{5}{2}$ are $\alpha$ and $\beta$ ($\beta > \alpha$) and the equation $(\alpha + \beta)x^4 - 25\alpha \beta x^2 + (\gamma + \beta - \alpha) = 0$ has real roots, then a possible value of $y$ is: