Guard cells are helpful in:

Assertion: The ferromagnetic substance does not obey Curie's law.
Reason: At Curie point, a ferromagnetic substance starts behaving as a paramagnetic substance.

The line $\frac{x + 1}{2} = \frac{y + 1}{3} = \frac{z + 1}{4}$ meets the plane $x + 2y + 3z = 14$ at the point:

The power dissipated in the circuit shown in the figure is $30 \, W$. The value of $R$ is ............. $\Omega$.

The magnetic field $(B)$ inside a long solenoid having $n$ turns per unit length and carrying current $I$ when an iron core is kept in it is ($\mu_0 = $ permeability of vacuum,$\chi = $ magnetic susceptibility).

In the circuit shown below,the resistances are given in ohm and the battery is assumed ideal with $emf$ equal to $3\, V$. The voltage across the resistance $R_4$ is ................ $V$.