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 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)

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 series AC circuit containing an inductor (20 mH), a capacitor (120 $$\mu $$F) and a resistor (60 $$\Omega $$) is driven by an AC source of 24V/50 Hz. The energy dissipated in the circuit in 60 s is :