Ge and Si diodes start conducting at 0.3 V and 0.7 V respectively. In the following figure if Ge diode connection are reversed, the value of V₀ changes by : (assume that the Ge diode has large breakdown voltage)

A carbon resistance has a following colour code. What is the value of the resistance ?

In the given circuit the the internal resistance of the 18 V cell is negligible. If R₁ = 400 $$\Omega $$, R₃ = 100 $$\Omega $$ and R₄ = 500 $$\Omega $$ and the reading of an ideal voltmeter across R₄ is 5V, then the value of R₂ will be :

A parallel plate capacitor with square plates is filled with four dielecytrics of dielectrics constants K₁, K₂, K₃, K₄ arranged as shown in the figure. The effective dielectric constant K will be :