A rod of length 50 cm is pivoted at one end. It is raised such that if makes an angle of 30^o from the horizontal as shown and released from rest. Its angular speed when it passes through the horizontal (in rad s^$$-$$1) will be (g = 10 ms^$$-$$2)

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 :

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 :

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)