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:
If the curves $$ 2x^2 + ky^2 = 30 \quad \text{and} \quad 3y^2 = 28x $$ cut each other orthogonally, then \( k = \)